No, not intercourse, but Sex. Biological sex. Or, as most people tend to think, "penis or vagina."
In the What Intersex does to the Gay Marriage Debate, we learned the intricacies of making a dichotomous male/female distinction. A penis, or lack of, does not necessarily indicate male or not male status, and as there isnt a good reliable measure of "male or female," the answer remains ambiguous for some people.
In Where the Bois Are, one lesbian remarks "If only you didn't have a penis." Which is what it comes down to with sexual orientation, the orientation of your partner's genitals. Men are worried that the cute girl they are hitting on has a dick under her skirt, and women worry (slightly less) that the penis attached to their partner isnt enough for them (or there at all).
But, we dont look at genitals when choosing our dating partners. And, the vast majority say that they wouldnt leave their partner if their penis was cut off in an accident. Yet, apparently "having" that penis, for heterosexuals, is a big part of what determines acceptable dating abilities.
So, if you sleep with a man who has a vagina? Or a woman who has a penis? Who the hell cares? Apparently many people do, on most places on the sexual orientation spectrum.
(Which is another rant: defining sexual orientation in a world without dichotomous genders/sexes.)