Looking at the admittedly small and unscientific sample size of my cousins, I find several instances of only girls being born to women who have only sisters. That is, out of a family of two sisters (no brothers), they have four daughters (no sons) among them, and another set of sisters (no brothers) also have only female children. Is this just a coincidence, or is there any evidence that the sex of your siblings may somehow influence the sex of your own children?
Remember that the sex of the child is determined by the male, not the female. The female has 2 X chromosomes, the male has 1 X and 1 Y. The resulting sex depends solely on whether the man’s X sperm or his Y sperm finds its way to the egg.
The family makeup of the mother has absolutely no bearing on the outcome.
But her body may have a lot to do with whether the X or Y sperm, or the resultant fetus, survives to birth or not. Perhaps some women have a biologic predisposition that favors female or male fetuses that they share with their sisters. There are some theories having to do with the acidity of the uterine environment being more favorable to one gender sperm, and that could possibly be biological.
We’re not exactly neutral incubators.
My sister’s husband’s family is quite large, and he has a pretty even mix of male and female siblings - I think it’s 5 male, 4 female. Or something.
Anyway, my point is that every one of these members of the family, both male and female, have had only female children. So my brother-in-law’s parents have about ten grandkids, and they’re all girls.
Odd.
One quick bump …
IMO…
If there were **any ** link at all between gender and just about anything, it would have been discovered long long ago. For most of history, most of the world has been trying to get boys. If there were a way to do it, they’d have done it.
Okay, but only to test out your theory!
I have two sisters and one brother.
My brother, with one male sibling and two female siblings, has two sons and no daughters.
I, with one male sibling and two female siblings, have two daughters and no sons.
Therefore, I don’t think the gender of one’s siblings has any effect on the gender of one’s children. Clearly this small statistical sampling is the be-all and end-all of the issue!
In sperm wars, Robin Baker suggests several things, including that external factors may influence what gender of offspring is more suitable for continued survival and prosperity. In particular, in lean times (whether the result of personal, financial, environmental, or societal conditions), it makes more sense to have female offspring, because they offer a larger number of potential descendants. He suggests that there is some degree of unconscious and imprecise selection of gender.
Baker also says that a woman unconsciously makes it more or less likely that she will conceive by, for example, “forgetting” to use contraceptives or timing the female orgasm in such a way as to make conception more or less likely – according to him, a female orgasm before insemination makes conception less likely while a female orgasm after insemination makes conception more likely. This method can also be used (again, unconsciously) to favor the sperm of one sex partner over another.