It is now in my headcanon that Qrow has a bunch of illegitimate children all over Remnant due to his Semblance causing contraceptives to fail.

As it turns out, back in the day, he donated to a sperm bank thousands of times for booze money. Due to a mix up the bank gave out his sperm to every couple that came in to get pregnant. He is now the biological father of hundreds of kids. Qrow is the Delivery Man.