My gut reaction is I'd prefer the pregnant daughter. Come back when I actually have a 17 year old daughter and son, and I'd almost certainly prefer my son be Gay.
The difference is, homophobe or not, nearly all men would rue the day their son came out. Fathers naturally want their son to be strong and masculine, because they hope their son will be like them. The adopted son of a gay couple would, of course, be accepted far easier. Its really a simple way of thinking, but it doesn't mean you're a homophobe.
As for the Daughter, all fathers are going to be protective of her and skeptical of most boyfriends she brings home. Seventeen is clearly too young to start a family for most girls, so almost all fathers would be quite mad over such a young pregnancy. I think given a night to sleep on it, most fathers would be able to accept the son's sexuality, but most would still be angry at the daughter.