To me, 3ven just doesn't have that flow that you want from a band name. Hard to say and hard to even decide how to try and pronounce it when you're reading it. You even had to tell us in the poll how to pronounce it.
OTOH, Gene Pool and the Shallow End is fun, campy, nerdy and to me, everything it sounds like you want your band to be. I'm not really getting the in-breeding reference. Never would have thought that if you hadn't pointed it out. The shallow end of the gene pool to me is just funny and self deprecating. Assuming that you are "Gene" and that you are the leader of the band, it just works.
To me, it's a no brainer.