Heh. Good comics. I voted for the first one.
I'm a hamster owner. It can be really hard to tell the sex when they're young. Petstores get it wrong all the time. (That said, same sex hamsters sometimes appear to be mating, and they're not. They're just asserting dominance.)
I've had better luck getting baby hamsters from a person whose hams have had a litter than from petstores, because you know how old they are (at around 4 weeks they can be separated from Mom and aren't old enough to get pregnant yet), but I did mess up the sex with my last pair and ended up with a boy and girl instead of a two boys like I wanted.
Err... yeah. Great comics.