Wait... if your religion is an unchangeable state of being, then why do Christians spend so much effort trying to convert people? And does she realize that interfaith marriages were illegal up until the last century?
*ahem*
1. Having dark skin is a phenotype that is expressed from birth and has a biological cause, so black people are indeed "born that way." While non-heterosexuality is not caused by genes, it does have a clear prenatal biological cause, so it is entirely accurate to say that queer people are also "born that way."
a. Even among black people, some black people have darker or lighter skin than others. Skin color is controlled by multiple genes, and even after that, environmental factors can influence skin color. It is variable and it can change.
2. Homosexuality is not a "mindset" and it is not a "mood." For instance, you are still straight even when you are not thinking about sex or sexual attraction.
a. "No one is born sexual" - Freud would disagree.
b. Bisexuality is not the ability to choose your sexual orientation. It is a sexual orientation in and of itself in that one is attracted to both the same and the opposite sex.
c. Sexuality in some people is fluid - I can definitely say that there are times I am more attracted to the same sex and other times when I am more attracted to the opposite sex. But I do not "choose" any of those changes, they simply happen.
3. You were born with dark skin and with a female body and a female mind. That is unchangeable. But a person is not a Christian from birth. I'm pretty sure salvation isn't hereditary in your religion. A person born to Christian parents can still be raised by a family of another faith and consider themselves to be of that faith. Heck, even in Judaism, where "Jewishness"
is hereditary, a person could be born to a Jewish mother (thus qualifying them as a Jew) but raised in another faith and come to identify with that faith.
4. Whether or not homosexuality is a choice has no bearing on whether same-sex marriages should be legal or not.