Today you can have two dads. In the future, you could have two biological dads.

The ability to create a baby mammal has always depended on a sperm and an egg. But now researchers have found a way to form mouse embryos from a pseudo-egg that tricks sperm into thinking they're fertilizing a normal one. It's never been possible before to use anything but the full sperm-egg combo, so this is a major step away from that paradigm. We are moving towards a future where we aren't limited by having a man and a woman to conceive a child.

These scientists injected sperm into something called a parthenogenote, which is derived from a mouse egg cell, but which can't become an embryo on its own. This is a brand-new technique never used before, published in Nature Communications this week. Human parthenogenotes can only survive for a few days before dying, but other animals use them to reproduce. Certain kinds of geckos, lizards, snakes, snails, spiders, crustaceans, and flatworms can all reproduce asexually using their own kind of parthenogenote that doesn't require sperm to develop into an embryo.