The black background looks sort of odd. Also the way he is holding that baby a long with his expression looks really sinister. Not sure if that is what you were going for?
I don't see sinister at all. I like everything about this photo, even down to the composition, exposure and contrast. On camera flash, though, right? But what the heck, it's a real keeper.
It wouldn't look like he's choking the baby so bad if the baby didn't have his eyes closed and a scrunched up face. I would repose, cause the lighting seems good.
This is one of the crummy parts of photography. When you finally find out what needs to change in your photos, the shoot is over. But hopefully the baby will be able to model for you again sometime.
I agree with the others - not liking the choking implication. I realize the baby is brand new and can't hold his head up yet, but you need to find a way to display him/her in a manner that comes across to the viewer as more loving.