While it would 100% be good to be built actually in game, I thought I should let you know there's actually a mod that adds this.
It's Kawaiistacie's explore mod, it adds a huge amount of rabbit hole locations and events that I just find really good. Highly recommend it. In this case I think you can also pick the sperm donor.
Here's a link: https://www.kawaiistaciemods.com/post/the-explore-mod
You can also use MCC to do the same thing if you want. But it doesn't have any rabbit hole or anything, it's just a cheat.