Why Are So Many Parents Picking Their Baby’s Sex?

In our on-demand era of reproductive liberty and technology, a child’s sex isn’t always left up to chance. As more parents have the option of choosing the sex of their baby before getting pregnant, they’re walking headfirst into an ethical quandary of what this means for their family and the prospective baby. But as any parent who has ever projected a desire onto a future child—which is, sadly, nearly all of us—what does it mean when we want a child of a specific sex, and what if they fail to meet that gender-stereotyped standard?

The United States and Western Europe are not facing the staggering sex-imbalance of China and India, but opting for one sex over another still has consequences, says Ruth Macklin, professor emerita at Albert Einstein College of Medicine and author of The Ethics of Sex Selection and Family Balancing.

The most obvious unexpected outcome is that parents who want a boy to do masculine things, like playing football, or a girl to do feminine things, like ballet or wearing dresses, may get a child who prefers...