The phrase "heterosexual marriage" refers to the union or partnership between a man and a woman. It describes the legal and social commitment that a heterosexual couple makes to each other. Full definition
There is good reason to affirm the value of heterosexual marriage for children and society. (religion-online.org)
I say this as one who clearly believes that any sexual activity outside heterosexual marriage is wrong. (redeeminggod.com)
It will surely make it more difficult for parents or the churches to argue a preference for heterosexual marriage (which I hope they will wish to do). (religion-online.org)