Male-female married couples are clearly linked to procreation because they have the categorical potential to procreate.
Second, same-sex marriage advocates sometimes assert that since procreation can and does occur outside of marriage, this shows that the state's interest in procreation is hardly a prime purpose of marriage.
Third, proponents of same-sex marriage sometimes argue that the procreation justification for male-female marriage is underinclusive because gay and lesbian individuals can and do procreate, either by sexual intercourse with someone of the opposite sex, or by means of artificial reproductive technologies.
Rather, the incentives of marital status should be used to encourage commitment of both mother and father to procreation and childrearing.
Fifth, some advocates of same-sex marriage deny that the "survival" procreation argument is still a valid social interest, arguing that the threat of overpopulation has made this argument obsolete.
Sixth, some advocates of same-sex marriage argue that even if furthering social interests in procreation was once a valid purpose of marriage, it has been replaced by partner intimacy.
It is very unlikely that they can show that legalizing same-sex unions will further social interests in procreation relating to survival, health, linkages between procreation to child rearing and between parent to offspring, and social order.
Two of the three American courts that have reached decisions favorable to same-sex marriage have discussed the validity of state interests in marital procreation as a justification for disallowing same-sex marriage.
excluding same-sex couples from the legal benefits of marriage" which was "the government's interest in furthering the link between procreation and child rearing.
Unfortunately, after clearly identifying the State's main claim regarding marital procreation (that it furthers the state's interest in linking procreation with child rearing), the court never analyzed that interest but spent its time attacking a "straw man" version of the State's asserted interests.
Allowing male-female couples who cannot or will not procreate to marry does make the law overinclusive (not underinclusive) vis-a-vis the purpose of linking procreation and child rearing, if the purpose of the law is that every married couple procreates.
Allowing male-female couples to marry, even those who cannot or will not procreate, conveys a message that links marriage with procreation because, as a category of unions, male-female unions are capable of human procreation (and most do procreate).