Michael Phelps and his wife Nicole revealed on Tuesday their son Boomer will soon be a big brother. The parents co-ordinated their announcement via Instagram. Per his Instagram caption, Boomer is amped to be a big brother. His mom and dad seem to not yet know the sex of the baby (nor did they announce when the baby is due), but it's safe to start making "are the Phelpses trying to make an entire Olympic diving team or what?" jokes now.