Some people may be predisposed to having children of just one sex.
That’s the conclusion of new findings published July 18 in Science Advances. While the chances of having a male or female child across whole populations may resemble a coin flip, for many individuals — especially those who have their first child later in life — the odds might be skewed toward one outcome.
The probability of conceiving and birthing a male or female child is theoretically about 50-50. This is because at least initially, equal proportions of sperm cells carry X and Y sex chromosomes, which are a major — though certainly not the only — factor determining