Random Chaos

Well since Kuja has a huge bitterness over being an artificial lifeform to the point that he believes he is immortal (also helped by the fact that he doesn't age) I'd imagine that he would forget that he's able to breed. It's not that he'd forget he had the equipment, more sort of he'd forget that he was given the equipment because of the reasons of his birth.

You saw how protective he got over Ziddy in report 01 (All the stuff he says to 589 right before Ultimecia pops up is genuine, plus he gives up his chance to leave Chaos to make sure they all leave safely) so of course he'd get incredibly OMGWTFBBQ YOU'RE NOT WEARING TWO COATS, YOU'LL FREEZE! over Terra.

The power of MAMA BEAR compels him!