Where Do Boys Come From?

I bet you think you know the answer to that question, don't you? And you probably do, sort of -- I mean, if any of you are still seriously wondering how those male creatures in your house came to be, shoot me an email. I used to be a nurse, after all. I can explain these things.

But it turns out there's more to the process. A study published in the Journal of Evolutionary Biology suggests that some men are prone to making boys. This may explain why I have four sons.

According to the study, all men have a gene that influences their ability to father sons, daughters or both. If a man has the mm version of the gene, he produces more Y sperm and is therefore more likely to father sons. If he has the mf version, he produces roughly equal numbers of X and Y sperm and will likely father both sons and daughters. A man with the ff version, however, will produce more X sperm and more daughters.

Other theories also abound. One says that stressed-out moms are more likely to have a girl than a boy. (The stress hormones may make it difficult for male embryos to implant in the womb.) Another study says that richer moms have more sons.

What do you think? Do you think some women/men are more prone to producing boys?