Imagine a world where superpowers are conferred via Lamarckian evolution. If one or more of your parents are in a desperate scenario where a specific metahuman power would come in handy, and they survive regardless and later have a kid, the kid is born with that power.
@Tailsteak DC's metagene tends to work that way... Carriers are born with the plenipotent possibility to have *some* power, but it only manifests if you have, and in a form relevant to, a life-threatening crisis. Then once it's active it's (potentially) heritable.
@Tailsteak "tends to" work that way as in that's officially and explicitly how it works if it hasn't been retconned this week.