You might not realize this, but straight people have outdoor sex all the time. Was it the outdoor sex or the look she gave you that scared you? If so just take it as a compliment that someone found you attractive. How come one experience made you decided then and there that gays should not have kids? Pardon my words but that is a tad crazy.
I once got mugged by a white straight guy.. does that mean I should dislike all white straight guys????? All or nothing thinking can get you stuck in stuff. Oh by the way I am gay and white.
I would say.. anyone of any sex can have sex outdoors. Get over it.