Well, mine was an evolving thing - I don't consider this a spoiler since it isn't an event, but some others might so if you consider skills/breeding things a spoiler, don't read -
I had these three males who must've been triplets - all redheads with those black and white outfits, same age - they all had a tiny research skill but nothing else so even though I'm maxed on tech I stuck them on the table.
Later when all three were trainee scientists I decided I wanted to keep that research skill around, so I grabed a few of the youngest girls of breedable age even though the population was maxed, and just kept putting the guys on top of the girls until all three had a smidge of a breeding skill. Not much, just a teeny tiny bit of blue.
I come back a few hours later - all three of them have gone from Trainee Scientists to Master Parents! Apparently since the tech was maxed they took time off from research to go impregnant all the women they could.
All three of them are dead now. But it sure was funny to me. The redheaded mass breeding scientists.