GLBT: Can someone explain this Politically Incorrect joke?

its saying that gays luv to have things up their but holes, this baby is gay as it was born from gay dads, this is ridiculous however as babies have no ual identity, the mere image of a baby with a ********* sickens me, but its derogatory to gays as it implies they luv the fun, but im offended by the fact they include a baby in it