This is unbridled fascism from the American Left, mainly because of their pathological need to see themselves as modern, progressive and tolerant. From Washington News:
An initiative filed by proponents of same-sex marriage would require heterosexual couples to have kids within three years or else have their marriage annulled. Initiative 957 was filed by the Washington Defense of Marriage Alliance. That group was formed last summer after the state Supreme Court upheld Washington’s ban on same-sex marriage. Under the initiative, marriage would be limited to men and women who are able to have children. Couples would be required to prove they can have children in order to get a marriage license, and if they did not have children within three years, their marriage would be subject to annulment.