Category: Science in Ancient texts (Hindu Sanskar)
Hi Beautiful & Peaceful Soul,
In the previous blog, I have written about importance of fourth component of preconception program i.e., timing (Rtu) of conception (https://thepureknowledge.blogspot.com/2021/01/scientific-explanation-of-garbhadhana.html). Today, I will discuss about science behind the concept of conceiving the child of desired gender mentioned in ancient texts. This is also a part of Garbhadhana Sanskar.
Vishudh Manusmriti, states that 6th, 8th, 10th, 12th, 14th and 16th nights of Rtukala period (https://thepureknowledge.blogspot.com/2021/01/scientific-explanation-of-garbhadhana.html) are favorable for coitus to conceive a boy. And 5th, 7th, 9th and 15th nights of Rutukala period are favorable for coitus to conceive a girl.
It has been also stated that higher potential of Y sperm leads to birth of a boy while higher potential of X sperm leads to birth of girl.
(I) Sanskar Chandrika also quotes various theories for sex selection of child (27), some of these are:
1. Those who desire for a boy should mate on 6, 8, 10, 12, 14 and 16 nights (Yugam Nights) of Rutukala (for more details on Rutukala, please refer to my previous blog https://thepureknowledge.blogspot.com/2021/01/scientific-explanation-of-garbhadhana.html). Those who desire for a girl should mate on 5, 7, 9 and 15 nights (Ayugam Nights) of Rutukala. The same has been mentioned in Manusmriti as discussed above.
Now the question is, what is the reason behind such selection of gender? According to another book, Sanskar Bhaskar, on yugam nights sperm (seed of men) has a higher potential thus leads to birth of a boy (1). Since Y sperm is responsible for the birth of a boy, so can we say that these nights are favorable for Y sperm to fuse with X egg?
On ayugam nights, seed of women has a higher potential leading to birth of a girl. Since X sperm is responsible for the birth of a girl so, can we say that these nights are not favorable for Y sperm and thus allowing X sperm to fuse with X egg? Another question is, which factors influence the viability and motility of Y and/or X sperm responsible for the fertilization to egg on respective yugam and ayugam nights?
Lets try to understand. It is a well known fact that the amount of vaginal discharge at the time of ovulation is different for everyone and it can be up to 10-20 times more than other points in cycle. Cervical fluid allows sperm to enter the uterus and reach the egg at the time of ovulation. Changes in cervical fluid makes it difficult or easy for sperm to swim past cervix into the uterus. This also protects sperm from the acidic environment of vagina. An egg only lives 2-24 hours after ovulation but sperm can live much longer, often 3-5 days, in fertile cervical fluid due to its protective actions. Scientific studies suggest that for maximizing the likelihood of conception, intercourse should occur on days with optimal mucus quality regardless of the exact timing relative to ovulation.
This clearly indicates that cervical fluid is responsible for protection of sperm for conception. So, the environment of female reproductive tract definitely influences the viability and motility of X and Y sperm cells!
The cervical mucus has presence of sodium, potassium, calcium, magnesium, zinc, copper, iron, sulphate, bicarbonate, phosphate, magnesium, cadmium, silver and cobalt. The concentration of these constituents changes every day in female genital tract and thus may have a specific effect on X and Y sperm (4). However, does everyday condition of menstrual cycle affects the viability and motility of X and Y sperm and can we relate the concept of yugam and ayugam nights with this point? Let us explore some natural methods for sex pre-selection of offspring:
A. Natural Methods for sex pre-selection of offspring are:
a. Shettles Method: Shettles stated that, those who desire for boys should have sex 2 to 3 days after or as close to ovulation as can be. While those who desire for girls should have sex in the days immediately after menstruation and then stop at least 3 days before ovulation (3, 38, 41). His method is based on the idea that Y sperm prefers alkaline conditions while X sperm can withstand acidic conditions. Based on this idea, he has suggested the sex position, timing of sex and orgasm along with methods viz., douching and abstinence to achieve offspring of desired gender (31). Let us discuss about this in brief to have a clarity on how these points relate to sex pre-selection of offspring:
(i) Timing of sex: Shettles explained that the Y sperm is smaller, faster (move more rapidly in the female reproductive tract), short-lived and loses fertilizing capability more quickly than the X sperm. Due to this reason, it is advisable for a boy-desiring couples to mate on the day of ovulation as well as following two or three days (31). This will give an opportunity to the speedy Y sperm to reach the egg sooner than the X one (29).
However, a recent review has contradicted Shettles theory as it suggested that the size of sperm is not only associated with its chromosomal (DNA) content but may also be associated with its cytoplasmic content. In addition, it suggests that the variations in the cytoplasmic content of X and Y sperm introduced by meiosis and/or spermatogenesis are greater than those introduced by the sex chromosomes itself (11). Recent findings also showed almost no or non-significant differences in the shape and size of X and Y sperm. Thus shettles theory of Y sperm being smaller does not hold ground now.
Coming to the hypothesis that Y sperm is faster to swim if true, a man should always have a son, with an almost zero chance of having a daughter. Human sperm travels at the rate of up to 3000 micrometer/min. Some sperms move slowly at the rate of 1000 micrometer/min. Thus, a 55 micrometer long sperm covers 1000-3000 micrometer/min. Several researchers have concluded that the variation in DNA content between X and Y sperm may affect their motility and swimming behavior. However this is more complex due to the effect of oviductal fluid on the motility of X and Y sperm. Low pH, high temperature and increased oxidative stress retards motility in Y sperm, whereas motility of X sperm rapidly declines when sperms are incubated in high pH condition.
Thus, the second point of Shettles's method is also not supported by this review. It is not right to give a tag to Y sperm a fast swimmer than X sperm, as they respond differently according to the different pH, temperature and oxidative stress.
It is mentioned that high temperature increases the likelihood of producing girl. Supporters point to high levels of daughters among airline pilots. The same theory led to the idea that men who wear tight underwear are more likely to have girls than those who wear boxers (47, 51).
Shettles also mentioned that Y sperm is short-lived but according to this recent review the viability of X and Y sperm varies in different conditions such as in vitro and in vivo. Modern science says that X sperm can withstand acidic environment, high temperature and other physiological conditions for longer period of time than Y sperm in in vitro conditions. This study showed that the percentage of Y sperm decreases by 15% at pH 5.5 and increases by 8.9% at pH 9.5. Moreover, this study also showed that the percentage of X sperm increases by 12.7% at pH 5.5 and decreases by 7.2% at pH 9.5 (3). X sperm is more viable and stable than Y sperm under in vitro conditions. This is due to increased cytoplasmic volume of X sperm than Y sperm which in turn could lead to higher level of intracellular proteins and phosphates that acts as intracellular buffering components making X sperm survive in acidic environment (3, 11). Interestingly, it also has been shown that certain properties of Y cells may ensure their prolonged viability in the female reproductive tract (in vivo). Thus subsequently affects the lifespan of both cells in a distinct manner. An experiment performed in vitro mimicking the in vivo settings in the female reproductive tract reported that Y sperm survived for a longer duration than X sperm, and that Y sperm were more proficient to bind to Zona pellucida than X sperm (11).
Thus, it can be concluded environment in female reproductive tract (mostly fluid composition, pH and ionic concentration, and transcriptomic responses) affects the viability of X and Y sperm and helps in selecting the best sperm for fertilization and decide the sex of baby (11). For instance, viscous cervical mucus increases the chances for male offspring (4):
Question arises what is reason behind this? Since the cervical mucus produced during different phases of menstrual cycle has different consistency i.e., before ovulation, the consistency of mucus is gluey while it is clear, watery and slippery immediately before ovulation (8) and on the day of ovulation, the cervical fluid becomes very wet and viscous (9, 24). So, if insemination occurs close to the ovulation, when cervical mucus is most easily penetrable by sperm and is more alkaline within the 7 to 14 pH range due to surge of luteinizing hormone (32, 28, 31), this helps sperm to survive inside a women's reproductive system (7). As per my understanding perhaps, these conditions make Y sperm to swim quickly and is more likely to reach the ovum first. It is stated that the consistency of vaginal mucus is thin and clear in case of boys and thicker and stickier in case of girl child. Conversely, if insemination takes place several days before ovulation, most of the Y sperm will become non-viable before ovum becomes available for fertilization (32, 28) as decrease in pH due to the estrogen surge just prior to ovulation, favors the survival of X sperm which is the base of sex selection of offspring (3).
Along with cervical fluid, uterine and tubular fluid of female reproductive system in menstrual cycle influences the viability and motility of X and Y sperm. This discussion clearly shows that sex of offspring does not depend solely on father but environment of female reproductive tract plays a crucial role here. The sex of child also depends on mother which is supported by a hypothesis given by modern science. According to this hypothesis, during sexual process male partner surrenders semen into vagina to decide the fate of his millions of gametes. Woman is fully responsible for any change that takes place on sperm or seminal plasma in her system (4). Therefore, the environment of female reproductive system in different days of menstrual cycle makes the base of preselection of gender of offspring.
The question arises, if vaginal pH is normally acidic then how sperm protects itself to reach the egg passing through vagina, cervix, uterus, tube and egg?
The acidic environment of vagina is toxic to sperm because the optimal vaginal pH for sperm viability and motility ranges from 7 to 8.5, and reduction in sperm motility is seen at a pH of less than 6.0 (4, 5). Both seminal fluid and cervical mucus present within the posterior vagina are alkaline and act as buffers. Scientists also showed that during sexual intercourse and as a result of sexual excitement, the vaginal epithelium produces a transudate that lubricates and also elevates the vaginal pH to 7.0 within seconds. This decrease in acidity can be maintained for up to two hours after ejaculation. This physiological modification, associated with the alkaline pH of semen, temporarily protects sperm. Within about 1 minute after coitus, the ejaculate undergoes coagulation. This clot temporarily restricts the movement of sperm out of the seminal clot. This clot is then gradually liquefied during the next 20–30 minutes by seminal-fluid proteolytic enzymes produced by the prostate gland. At this time, motile sperm may enter the cervical mucus (cervix), leaving behind the seminal plasma (5, 6). Now consider another points on which Shettles method is based.
(ii) Abstinence: He suggested that to produce male child, couples should abstain from intercourse from the beginning of the menstrual cycle until the day of ovulation. The day of ovulation, as well as the following two or three days are when the chances of producing a male are the highest (39, 41). To produce female child, couples should abstain from intercourse two to three days before ovulation. Prior to that, intercourse is encouraged as the time between the end of menstruation and at least three days before ovulation is when females are more likely to be produced (31). I have discussed this in my previous blog (https://www.blogger.com/blog/post/edit/6634475558912675593/6110236925324962075, how abstinence is responsible to provide good quality of sperm. Sperm have better quality when collected after 2-3 day period of abstinence and higher rates of conception are seen in couples who have sex every 1-2 days (14).
(iii) Position during intercourse: To produce male child, couples should follow the position of deep vaginal penetration, this helps sperm cells get deposit close to cervix , where the environment is naturally alkaline, and they are more likely to survive the short journey. On the other hand couple should assume a face to face position and perform shallow penetration during intercourse to produce a female child. The slower X sperm can withstand the acidic pH when passed through vagina. In contrast, medical sceptics are of opinion that force of ejaculation and physics of sexual position does not play a part in getting the sperm to their destination more quickly-that is rather determined by the chemistry of cervical mucus (28).
(iv) Orgasm: It is a well known fact that the chemistry of secretion affects the environment of the reproductive tract. Thus, the secretion during female orgasm is alkaline and provides favorable environment for producing male fetus. If couple desires a female fetus, then the woman should refrain from having an orgasm at least until after the sperm has already been ejaculated to avoid the addition of alkalinity to the environment (31, 28). Prolonged foreplay has the same effect of increasing the vaginal secretion, which could be just as effective at reducing its acidity (28).
(v) Douching: It is flooding the vagina with diluted alkaline condition such as baking soda before intercourse (28). The Shettles method suggested different douches such as alkaline douche (diluted baking soda solution) for producing male fetus and acidic douche (diluted vinegar solution) for producing female fetus. According to him, these solutions are harmless to both the mother and fetus (31). According to him, the success rate of conceiving a girl with this method is 75% (35).
There are other theories related to timing of sex in modern science discussed below:
b. Dr John Martin Young, a Texas sex selection expert, believed couples are more likely to have a boy if they avoid sex around ovulation and more likely to conceive a girl if they have intercourse during ovulation.
c. Whelan method is claimed to be some 68% effective for boys and 56% for girls. It also centers on the timing of intercourse but suggests that chemical changes that favor producing a boy occur earlier in a woman's cycle. If a boy is wanted, intercourse should occur four to six days before your basal body temperature (temperature after waking up) goes up. This is because an increase in body temperature is associated with the presence of progesterone in the bloodstream after ovulation occurs and therefore a spike in body temperature indicates that an egg has already been released. Whelan wrote that women should consider the day before the temperature spike as the day of ovulation. Then, during their next cycle, women should have sex two to three days before they ovulate. She claimed that her method was supported by natural insemination (35, 40, 42).
However, some studies found no systematic differences in days of menstrual cycle produced boys and girls. Some studies clearly refute the theory that intercourse close to ovulation favors male conceptions (2, 43, 44)
But, till now it is understandable that to conceive with desired sex, women should know about the time and period of her ovulation cycle. By knowing ovulation period only, she can decide which method to use? Now question is, how to know ovulation period?
- General rule is 14th day of menstrual cycle, but there is a lot of ambiguity in it.
- Ovulation can be detected by Billing Ovulation method which is also called cervical mucus method. This method relies on tracking the changes in woman's cervical mucus to plan the best days to have or avoid sex. Cervical mucus is produced throughout the monthly menstrual cycle. The quality and amount changes throughout the cycle help a woman predict when she is going to ovulate. Detection of ovulation helps to identify most fertile days required to attain pregnancy. This also helps to select days on which sex should be avoided to prevent pregnancy. The typical phases of cervical mucus quality during the cycle includes:
Dry days of very little mucus; cloudy and sticky mucus leading to ovulation; clear and slippery mucus just before and during ovulation; cloudy and sticky mucus after ovulation. The most fertile days are near clear, slippery and stretchy cervical mucus (46). Thus, none of these methods have 100% results still, which method are you going to choose, ladies? Moreover, commercial sex selection kit are also available in the market. It is advisable to consult to your doctor.
B. Artificial methods for pre-selection of offspring: More advanced and artificial methods for pre-selection of gender of offspring includes sperm sorting or Ericsson's method, Microsort, Preimplantation Genetic Diagnosis (PGD) and Urobiologics PreGender test (30, 47). PGD has an accuracy rate of over 99%, making it the most precise method for gender selection available today. This is especially important for aspiring parents who want to use gender selection to reduce their chances of having a baby with a sex-linked genetic disease. While the Ericsson Albumin Sperm Sorting method is easier and less expensive than PGD. This technique can't do absolute and total separation between X-carrying sperm and Y-carrying sperm, making it less accurate than PGD (52).
Let us come back to another theories given in Sanskar Chandrika for sex selection of child:
2. If man is elder in age and stronger than woman, then the child will be boy and if woman is stronger then child will be girl.
I am not sure when does a woman is considered stronger than man. As per my understanding the meaning of strong woman is based on Ayurveda theory which states that a fatty woman finds it difficult to conceive and this is supported by modern science as well. Thus Ayurveda recommends a diet and herbs that makes man strong and woman healthy and not fatty. As per Sanskar Chandrika, thin and healthy woman can produce boy with a strong man.
A scientific study suggests that maternal weight at conception influences the gender of the offspring. Low pre-pregnancy weight is associated with a deficit of males. The results are consistent with a scientific report which showed that in rural Ethiopia, well-fed women were more likely to conceive males. The relationship between caloric availability and sex ratio has been observed across several countries and there is a higher energy demand for male embryos. This data again supports the theory suggesting higher production of females in non-optimal maternal conditions. Thus, this data strongly indicates maternal weight and maternal metabolism as important determinants of secondary sex ratio in human offspring. These also indicate that in women with non-optimal reproductive/metabolic conditions, a greater attrition is exerted on male than on female offspring. Hence, this study supports the theory suggesting mother should have optimal maternal conditions for a male progeny (14).
3. Another theory given in the book is that ovum from right ovary produces boy while ovum from the left ovary produces girl on fertilization. This theory however, is not very useful to conceive with desire sex as it is not possible to examine the ovary involved in ovulation. However, this method can be used for second child. For example, if first child is girl, then we can back calculate the month when ovum was released from left ovary. When woman again starts periods post parturition then we know that ovum will be released from right ovary and so on. After having first child, we can conceive with child of desired sex using this method.
Now, let us see what modern science has to say about it?
A scientific study showed that for both fertile and infertile women ovulation from the right ovary occurs more often than from the left ovary. Moreover, in both fertile and infertile women the fertility potential of oocytes from the right ovary surpasses that of the left ovary (13). Due to ovarian asymmetry, X and Y sperm may respond differently to signals from right and left ovary (15) and the battle of the sexes starts in the oviduct providing first molecular evidence of a sex-specific sperm recognition system in the oviduct (16).
This shows that ovum (women's egg) has a choice to attract sperm. This is supported by recent study in year 2020 which stated that even though the fastest and most capable sperms reach the ovum first, it is the egg that has the final say on which sperm fertilizes it. A chemical communication occurs between the female reproductive system and the incoming sperm cells. The chemo-attractants are released from the eggs which allow the egg to choose between the sperms swimming towards them. Only around a few hundred sperms reach the follicles or tubes where they meet the follicular fluid, which has these chemo-attractants to attract the sperms (17, 18).
Now question is, what is the basis on which egg sends these chemical signals to attract sperms?
The egg does not always pick the sperm of a women's partner, sometimes egg finds sperm from some other person more attractive. Since sperm functions only to fertilize eggs, researchers think that the choice is entirely up to egg, which benefits from selecting sperm that is of higher quality or somehow more compatible (19, 20, 21). Thus it is hypothesized that eggs are likely to attract a more genetically compatible sperm (22). Thus, can we say that the chemo-attractants present in the follicular fluid of different ovaries signals X and Y sperm differently?
Thus far we have studied that physiological factors play a role in the selection of gender of offspring. There are other non-physiological factors which affect the acidity of vaginal and cervical fluid. These are stress, obesity, unbalanced hormones, age, dehydration, medications and radiations, environmental toxins and diet (7).
These factors also affect males. For instance, men produce approximately 50% X and Y sperm (11). However, exposure to high levels of hormone-disrupting chemicals or radiation can skew the ratio of male and female sperms. High stressed jobs also skew the ratio of sperms leading to birth of more daughters (34). Studies have repeatedly found that one of the reliable predictors of sex of the offspring is the age of the parents. Older parents are significantly more likely to have daughters than younger parents (48). Moreover, diet plays a role in the pre-selection of gender of offspring (28, 35). Studies showed that increased calorie intake and eating breakfast cereals inturn increases the chances of having a baby (36). The maternal diet high in sodium and calcium, in combination with timing of intercourse well before ovulation has been found to improve the chances of conceiving a girl (49). There is also wide spread use of indigenous medicines for sex selection.
Hey friends, I am not advocating any technique to pre-select the gender of offspring. The sole purpose of this article is just to give an idea about what our ancient texts said and where science stands on them.
I feel really proud to be born in India as our ancestors were so wise with vast knowledge of biology. They gathered all this information and wisdom in "Aadikaal" which modern science is still trying to achieve. I hope my efforts in explaining theories given in Sanskar Chandrika and Manusmriti in relation to modern science will be of some help.
Take Care
Your's Sincerely
Purnima Ghai
References:
1. Book: Sanskar Bhaskar
2.https://www.nejm.org/doi/full/10.1056/NEJM199512073332301
4.https://scialert.net/fulltext/?doi=tmr.2011.161.168
5.https://www.scielo.br/pdf/medical/v2n2/2318-8111-medical-02-02-20150207.pdf
7.https://www.storkotc.com/blog/how-your-bodys-ph-levels-can-affect-fertility/
8.https://www.healthline.com/health/womens-health/cervical-mucus#stages
9.https://www.medicalnewstoday.com/articles/323503#cervical-mucus-timeline
12.https://academic.oup.com/humupd/article/12/1/23/607817
13.https://academic.oup.com/humrep/article/15/9/1921/2915355
14.https://academic.oup.com/humrep/article/19/2/442/2356346
15.https://www.biorxiv.org/content/10.1101/418186v3.full
16.https://bmcgenomics.biomedcentral.com/articles/10.1186/1471-2164-15-293
18.https://www.news-medical.net/news/20200611/The-egg-decides-which-sperm-fertilizes-it.aspx
19.https://www.labroots.com/trending/genetics-and-genomics/17865/human-eggs-choose-sperm-prefer
21.https://phys.org/news/2020-06-human-eggs-men-sperm.html
22.https://www.bionews.org.uk/page_150196
23.https://pubmed.ncbi.nlm.nih.gov/9130769/
24.https://helloclue.com/articles/cycle-a-z/wet-sticky-what-your-discharge-is-telling-you
26.https://www.bmj.com/content/331/7530/1437
27. Book: Sanskar Chandrika
29.https://www.webmd.com/baby/features/choosing-sex-of-your-child#2
31.https://embryo.asu.edu/pages/shettles-method-sex-selection
32.https://www.fertstert.org/article/S0015-0282(16)47904-5/pdf
33.https://www.nejm.org/doi/full/10.1056/NEJM199512073332301
34.https://www.newscientist.com/article/dn19048-bumpology-choosing-the-sex-of-your-child/
35.https://www.healthline.com/health/whats-the-right-diet-to-conceive-a-girl#the-science
36.https://www.healthline.com/health/pregnancy/diet-to-conceive-a-boy
38.https://www.healthline.com/health/pregnancy/shettles-method
39.https://www.sciencedirect.com/science/article/abs/pii/0020729295025068
41.https://www.healthline.com/health/pregnancy/shettles-method#trying-for-a-girl
43.https://www.fertstert.org/article/S0015-0282(16)47904-5/pdf
45.https://www.verywellfamily.com/the-billings-ovulation-method-1960231
46.https://my.clevelandclinic.org/health/treatments/21066-cervical-mucus-method
49.https://www.rbmojournal.com/article/S1472-6483(10)00549-3/pdf
51.https://daily.jstor.org/climate-gender-males/
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great share loved it ,I think there should be a extensive study on this further , like a huge dataset from all around the world to know its accuracy for verifying
ReplyDeleteThank you so much for your appreciation.
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