Legal Question in Insurance Law in California

No, because it is not invidious discrimination. Homosexual couples are allowed to get benefits because the law prevents them from being "married". You are not married by your own free choice and there is a very simple remedy to your problem.

It depends on whether same-sex couples who are not registered domestic partners can get the benefits. The reason for the same sex or 62 requirement is that those are the requirements for a couple to register as domestic partners. Homosexual couples cannot marry, and there are social security and estate planning issues once you are over 62 that can create problems for couples who marry after that age. Heterosexual couples can marry. There are some, but very few differences between domestic partnership and marriage. So it is perfectly legal for an employer and the employer's insurance plan to require you become a formal legal couple by the method available to you, before allowing partner coverage. If they are allowing same sex couples who are not domestic partners to insure partners, but not heterosexual couples THEN you MIGHT have a case and should talk to an attorney in person.