Adopting my babu

So im having my 2nd child. I have my brother and his wife that is having problems having a baby. So my husband and i decided they could keep my baby. But they only want the baby if its a boy. I feel sorry for them because there been trying and nothing. But the only thing is i have this feeling that if i give birth i might change my mind. I really want them to have the baby but just knowing that i carried it and everything i will get hurt. Is this a bad thing. Just want to know if anyone has been in my situation