They say that an apple doesn't fall from the tree. Well, when it comes to the gender of children, it seems this old saying rings true for men who want to know whether they're more likely to father boys or girls—just check your family tree, The New York Times reports. A British study released in December found that some men carry a gene that predisposes them to fathering more boys, more girls or equal numbers of each.
The father, who provides the deciding chromosome, either an X or a Y, determines a child's sex. The study of more than 900 U.S. and European families—published in the journal Evolutionary Biology—discovered men carry a gender-controlling gene that determines the percentage of X and Y chromosomes in their sperm.
Researchers said the findings explain how the human race keeps a fairly even balance of men and women despite massive deaths of males in wars and selective abortion of female fetuses in certain parts of the world. Women also carry the gene, but it's recessive. So when there are few males around, men have a higher chance of mating and passing along their pro-boys gene. In reverse, when there are fewer women around, they're more likely to pass on the female-version of the pro-daughter gene.
Confused? Well there's always the old rule of thumb: Men who come from families with a high number of males have higher odds or fathering boys, and vice versa for dads-to-be with many sisters.
But remember, don't believe every single myth that you hear about how to determine your baby's gender, as our Ask the Labor Nurse blogger explores.
Are you planning on finding out your baby's gender before your due date? If you're worried that you'll be disappointed if you find out, check out our Gender Letdown feature and then share your feelings with us.
Maria Vega is Fit Pregnancy magazine's copy editor.