Reproduction is messy. The genetic swaps and recombinations that occur when gametes merge don't always happen perfectly. Babies don't arrive when scheduled. Even preventing reproduction can be complicated, as anyone who has ever wrestled with birth control can attest.

That said, it's arguably a better time than ever to have a baby. Prospective parents struggling with infertility can turn to IVF, or sperm and egg donation. But as the egg donor industry grows more sophisticated, the donors themselves are sometimes kept in the dark. Once a person becomes pregnant, they can take advantage of the extraordinary advancements in noninvasive prenatal testing to screen for chromosomal abnormalities and genetic mutations—but then, what actually happens to the mountains of genetic information these tests generate?

Or maybe it's the worst time to have a kid. Mounting societal concerns—political upheaval, climate change, the general crushing financial and psychic toll children impose—make procreating seem like a spectacularly bad idea. People who opt to go #childfree certainly think so. And still-high prematurity rates, especially among minorities, show that science alone can't solve every problem.