Men carrying a gene that leads to their sperm having more Y chromosomes have more sons. During times of war and large casualties of male soldiers, those families are more likely to have more surviving sons. And when those men have children, they, like their fathers, might be more likely to have baby boys.
Timing of intercourse
The timing of when a couple has sex is thought to actually make a difference in helping to conceive with a boy. It is one of the strategies suggested in The Shettles Method, which claims that the chances of having a boy are boosted when conception occurs as close to ovulation as possible.
Nature is designed to favour the conception of boys from September to November and girls from March to May because of an evolutionary mechanism aimed at keeping the overall sex ratio as near to 50:50 as possible, the scientists said.
Among the 498 (9.4%) women with times to pregnancy longer than 12 months, the probability of male offspring was 57.6% (287), whereas the proportion of male births among the 4785 women with shorter times to pregnancy was 51.1% (2445, χ2 = 7.81, P = 0.0052).
There are many ideas about ways to influence baby's sex and how to conceive a boy or a girl, but these are mostly myths or "old wives' tales" that aren't supported by modern science. The only reliable way to choose a baby's sex is by using IVF with genetic testing.
Every egg has an X sex chromosome; a sperm can have either an X or a Y sex chromosome. If the sperm that fertilizes an egg has an X chromosome, the baby is female; if it has a Y chromosome, the baby will be a boy.
While most families have an imbalanced sex ratio, other parents can't conceive boys or girls, and some even believe that girl or boy genes “run the family.” But researchers still haven't found any shred of evidence that proves if some families can have only males or females because of their genes.
50/50 chance of each. It depends on which sex of sperm gets to the egg at the right time, and sperm don't know you were ever pregnant with a boy or girl. It's like flipping a coin every time you get pregnant. 50/50 chance of each.
Note: The only way to choose your baby's gender, would be to go for in vitro fertilisation (IVF), where the egg is fertilised with the man's sperm in a laboratory. Doctors are able to check the gender of the embryos before re-implanting them in the mother.
The key to conceiving a boy is to do “the deed” close to your ovulation. As Dr Shettles points out, male-producing sperm (Y-chromosome) move faster than female sperm. Male sperm also dies pretty fast, while female-producing sperm (X-chromosome) can stick it out and take their time hooking up with the egg.
Almost everyone has around a 50% chance of having a boy and a 50% chance of having a girl. What we can say is that dad's sperm determines whether a baby will be born as a boy or a girl. About half of his sperm will make a boy and half a girl. The sex of the baby depends on which sperm gets to the egg first.
If you have two children, you'll have a 50% chance of having a second boy, based on the ratios above. Then if you have three children, you'll have a 25% chance of having all three boys, and a 75% chance of two girls and a boy or two boys and a girl. Yes, genetics can play a part, but it all comes down to chance.
All men inherit a Y chromosome from their father, which means all traits that are only found on the Y chromosome come from dad, not mom. The Supporting Evidence: Y-linked traits follow a clear paternal lineage.
According to conventional wisdom, an embryo becomes a boy when a gene on the Y chromosome triggers the development of testes, which then begin to produce male sex hormones, including testosterone, at about the 8th week of gestation.
Unlike nuclear DNA, which comes from both parents, mitochondrial DNA comes only from the mother.
Use of cocaine or marijuana may temporarily reduce the number and quality of your sperm as well. Alcohol use. Drinking alcohol can lower testosterone levels, cause erectile dysfunction and decrease sperm production. Liver disease caused by excessive drinking also may lead to fertility problems.
There is no specific frequency with which a man should ejaculate. There is no solid evidence that failure to ejaculate causes health problems. However, ejaculating frequently can reduce the man's risk of getting prostate cancer. Ejacu-lation can be through having sex or masturbating a few times a day.
Healthy sperm have rounded heads and long, strong tails. Shapely sperm are more likely to make it to an egg.
On the other hand, having sex from 2 days before ovulation, through a few days after ovulation, is better for conceiving a boy. Around the 2-day point, 48 hours before ovulation, seems to be the 50/50 mark. (2) The pH of the women's tract is also very important.
The proportion of male babies was significantly higher (65.5 +/- 3.9 per cent, mean +/- S.D.) in the offspring of women who resumed intercourse two days after ovulation. This proportion tended to be lower on or near the day of ovulation than on the previous one or two days.
However, if semen is often very thick, it can signal a problem with the prostate or the seminal vesicles. If a person has very thick semen, a doctor may refer to the issue as “semen hyperviscosity.” If semen is very thick, the sperm cannot move as easily and there may be fewer sperm.