The Psychology of Magi

Schadrit & Jiphella of Dankmar from GotF both used a faerie charm to have children post LR.

A version of this, making a homunculus, already exists, as I recall. I don't think the homunculus grows and thrives, though. Further research required.

It doesn't. Also, it's faerie magic.

An actual merger of male and female sperma to create a human embryo, quoth A&A pg. 36, is something that should be possible by Hermetic magic but that nobody's figured out yet.