I'm not interested in how the heterosexual society and its institutions define it!
Here are my own reservations about the definition:
DEFINITION OF HETEROSEXUALITY
The thing with English language is that the same word can mean so many closely related but obviously different things, that it is easy to manipulate and do selective usage of these terms to distort the truth subtly but immensely.
E.g., when talking about numbers of homosexuals, people tend to define it as those who have 'exclusive' sex with men. So you have a number of 10%.
But when they talk about numbers of heterosexuals, suddenly, the definition includes anyone who has ever had sex with females, and no exclusivity is needed. So then you have a percentage of 90% of heterosexuals.
Yet again, when it is like exerting the social power of 'heterosexuality' or to marginalise same sex behaviour, then it is back to heterosexual is 'exclusive' sex between males and females as is evident from the examples on this thread on sci-forums:Calling all heterosexuals
Look at some of the ways people define heterosexuality here:
"How can someone define themselves heterosexual and still be attracted to the same sex?
Heterosexual by definition means "Sexually oriented to persons of the opposite sex." So this poll is technically invalid, if not, then people's definitions of their own sexuality are skewed."
This pretty much aptly sums up the common perception of 'heterosexuality', (but which conveninetly changes when talking about the percentage of heterosexuals).
It's also because of the social pressures --- that anyone who has (whether willingly or unwillingly), sex with women will call himself 'heterosexual' whether or not he has lots of sex with men.
While, it is only he who is exclusively into men, who will call himself 'gay'.
But science will be completely a useless institution if it further adds to the confusion by not defining what it really means by the terms it uses.
And to use a definition (whether it is heterosexuality or homosexuality) which is against the popular usage of the term is also creating deiberate confusion on the issue and should be considered unethical for scientists.