Why does he have a zipper on his chest :|
(dunno if it's a zipper or not but it looks like one to me :P)

it is a zipper and it's not on his chest. it's on his stomach above his groin, and it's kinda explained in my other ref but what it does is allows him to "switch" sexes. normaly he has girly parts but he can open that zipper up and push a special button and it allows him to switch, it was a special surgury that the aliens that abducted him did before the actual genetic reformation. reformation completed the procedure and allowed him to heal fully.

not sure how I feel about that :|
whatever.

*shrug* you don't have to like it, but you asked so i explained. :/