Whenever I go out in public, I notice pairs of mothers and daughters. Once kids hit adolescence, you rarely see mothers and sons, fathers and sons, or fathers and daughters spending much time together. But mothers and daughters of all ages apparently tend to enjoy each others’ company.

The upshot is that if you’re a mother without a daughter, you’re probably missing out on one of the best relationships you’re likely to have in this life. Per my earlier advice, I’d recommend having another child. Maybe she’ll be a girl and you’ll have a lifelong companion.

But what if it’s yet another boy? I’ve often heard women express pity for moms with a three or more boys, but I’ve never heard them sympathize with moms with three or more girls. In all likelihood, then, there are a lot of women out there who want one more baby girl, but don’t want a 50% chance of getting one more baby boy instead. In terms of expected utility equations:

EU(one more girl)> EU(status quo)


.5*EU(one more girl)+.5*EU(one more boy)< EU(status quo)

Technology to the rescue! There is now a highly effective and surprisingly affordable way to "stack the deck," to get a baby with the gender you're looking for. It's called “sperm separation”:

[T]he X chromosome is substantially larger than the Y chromosome… Since chromosomes are made of DNA, human sperm cells having an X chromosome will contain approximately 2.8% more total DNA than sperm cells having a Y chromosome. This DNA difference can be measured and the X- and Y-bearing sperm cells individually separated using a modified flow cytometer instrument.

What about effectiveness? If you want a girl, you can raise the probability to 91%. If you want a boy, you can raise it to 76%.

The price charged by one leading firm is only $3000 for the first vial, and $650 for additional vials. That’s probably less than you’d spend on braces, these days.

You might think that this technology is only for people with sex-linked genetic disorders, but that’s not so. The industry is happy to offer its services to couples seeking “family balancing,” too.

The bottom line is that if you want another child conditional on getting your preferred gender, the market is ready to help. And while many people will object to this “commodification of human life,” it’s hard to see how all their grumbling can withstand the straightforward counter-argument: “Meet Jane, a person who only exists today because her parents were allowed to stack the deck.”