A free society based on mutual respect would normally be expected to provide legal facilities for lifestyles chosen by significant groups. Why then do gay activists wish to prevent heterosexual couples from having separate legal recognition? Sometimes it is said that there is no difference between same-sex and dual-sex relations because both are based on love. But that claim assumes that marriage is largely about the couple, when traditional marriage has not merely been about mutual support. Above all, it has been for the sake of children. A man and a woman in a sexual relationship are highly likely to have children. Traditional marriage recognises that fact. It does not matter that babies do not arrive in every case. It is a strong possibility, which is enough to have a legal arrangement to ensure that helpless infants will be brought up by loving parents. There is a strong public interest in encouraging the best possible arrangements for raising children. 

It is reasonable to have a different legal arrangement for same-sex couples because, no matter how much sex occurs between them, a baby will never result from it. The possibility of adoption makes no difference to the argument, because it always requires a separate legal procedure. Artificial insemination also makes no difference to the argument because it too is subject to specific legal regulation. And if a woman in a same-sex relationship is impregnated by a man, separate legal obligations for the father and mother will apply in such cases. None of these possibilities contradicts the inescapable fact that sexual relations between same-sex couples will never produce babies. That unavoidable difference justifies having a different legal institution. Having distinct legal arrangements for gays and straights leaves both free to live as each believes right. 

The hostility of gay activists to legal diversity suggests that there is something deeply illiberal about their demands. When homosexuality was legalised back in the 1960s it was a liberal measure in the normal sense of the term: it widened the bounds of civil society, where moral persuasion is the guiding principle, and narrowed the bounds of political society, where enforcement is the norm. We were free to discover and debate the rights and wrongs of this or that sexual conduct without the heavy-handed intrusion of the law. But today's activists are demanding the suppression of legal diversity. They want the law to deny separate recognition to traditional marriage, even though it is the preferred choice of the great majority. 

This demand suggests a degree of animosity that goes well beyond a wish for personal freedom. The gay community has been hijacked by a few activists who claim to speak for all gays and lesbians, when they speak only for themselves. The majority of gays and lesbians accept that the utmost freedom for them to live as they wish is perfectly compatible with a different legal facility for male-female couples alongside civil partnerships for same-sex couples. They see no need for an act of aggression against traditional marriage. The law should be left as it is.