US Permanent Resident Parents and UK Citizen New Born - Travel

Yes you will be able to bring the baby alone but only if you seek to do so on your very first trip back to the USA. Before you travel, contact the consulate for details.

Because you and your wife are both lawful permanent residents, your child will automatically be a lawful permanent resident without filing any I-130 petition as long as you do the following: the child MUST accompany you on YOUR first trip back to the U.S. after the child's birth. You cannot secure automatic LPR status for your child if you travel back to the U.S. without the child with intent to bring the child on your second trip after his birth. It must be your first trip to the US after his birth. You also must make certain the border officer who inspects you (and your child) knows your child is entitled to automatic LPR status and initiates the required paperwork to trigger production of the child's green card. If you have any doubt about whether the officer knows what s/he is doing, request a supervisor. I once had a client whose life got thoroughly disrupted because the border officer did not do what he was supposed to do and the parents had no idea the border didn't know what to do because they didn't know what to do either.

I agree with the other answers. I suggest you speak with a lawyer before doing anything to make sure you understand the process.