This is beautiful. Why didn’t I know this already?
Fingerprints are formed by friction from touching the walls of our mother’s womb. Sometimes they are called “chanced impressions.” By Week 19, about four months before we are issued into the world, they are set. Gorillas, chimpanzees, and koalas also possess exclusive prints.
— Read on www.theparisreview.org/blog/2018/05/15/the-surprising-history-and-future-of-fingerprints/
It’s more the fetus touching the amniotic sac combined with genetics, but it’s still a striking thought. Here’s a helpful video I found on the topic.