I feel like I need to mention, as a trans woman - regardless of what genital configuration Claire may currently have, and regardless of whether or not she plans to some day have bottom surgery - which is, of course, none of our business - she is a *woman*. A man who sleeps with a trans woman in no way, shape, or form stops being straight, *regardless* of the genital configuration of that woman. Whatever she has downstairs, they're a *woman's* genitals, and last I checked, when a man and a woman have sex, that's usually considered pretty straight. Whatever Claire and Marten get up to, unless they invite a third person, it will be straight sex.
Sorry for the whole big speech, I just didn't see anybody getting this point across, and it was really important to me. I get a little militant on that point, because too many men are shamed by their friends and peers, and have their heterosexuality and identity questioned or mocked, if they date or sleep with a trans woman. It not only keeps too many of my sisters cold on lonely nights, it can also be a major driver for violence against us.