Cynthia Nixon's claim to be gay by choice riles activists

RELATED: Gay for a Day

Nixon's publicist did not respond to an email asking if the actress wished to comment on the criticism.

While the broader gay rights movement recognizes that human sexuality exists on a spectrum, and has found common cause with transgender and bisexual people, Nixon may have unwittingly given aid and comfort to those who want to deny same-sex couples the right to marry, adopt children and secure equal spousal benefits, said Jennifer Pizer, legal director of the Williams Institute on Sexual Orientation and the Law, a pro-gay think tank based at the University of California, Los Angeles.

One of the factors courts consider in determining if a law is unconstitutional is whether members of the minority group it targets share an unchangeable or "immutable" trait, Pizer noted. Although the definition of how fixed a characteristic has to be to qualify as immutable still is evolving — religious affiliation, for example, is recognized as grounds for equal protection — the U.S. Supreme Court still has not included sexual orientation among the traits "so integral to personhood it's not something the government should require people to change," she said.

"If gay people in this country had more confidence that their individual freedom was going to be respected, then the temperature would lower a bit on the immutability question because the idea of it being a choice wouldn't seem to stack the deck against their rights," Pizer said.

Nixon stirred the identity politics pot further when she explained in a follow-up interview with The Daily Beast this week that she purposefully rejected identifying herself as bisexual even though her history suggested it was an accurate term.

"I don't pull out the "bisexual" word because nobody likes the bisexuals. Everybody likes to dump on the bisexuals," she said. "But I do completely feel that when I was in relationships with men, I was in love and in lust with those men. And then I met (her fiancée) Christine and I fell in love and lust with her. I am completely the same person and I was not walking around in some kind of fog. I just responded to the people in front of me the way I truly felt."

Although science has not identified either a purely biological or sociological basis for sexual orientation, University of California, Davis psychologist Gregory Herek, an expert on anti-gay prejudice, said Nixon's experience is consistent with research showing that women have an easier time moving between opposite and same-sex partners.