Originally Posted by
infradig
It's not clear if the OP was denied an op-up or had a SWU revoked, but I've had an op-up with an infant in arms on a TATL flight (Plat with wife Silver) and I've used SWU with an infant (also TATL), but I did have to pay the fare difference for BE for the INF ticket.
OP said she was on an award ticket. They cannot be upgraded with miles or SWUs into international BE.