What if homosexuality is proved to be genetic?

Back in Biblical times, people didn’t know that homosexuality could have been genetic, and assumed it was a choice. And also saw it as a huge sin because God designed us to have sex and reproduce. But if homosexuality turns out to be a genetic thing, won’t it completely disprove everything that hardcore Christians have always stood for? And if it is genetic, that means it’s in their DNA and makes up who they are. And because God made us all, and DNA is part of us, won’t that mean that God intended that person to be homosexual? What will a homophobic Christian have to say to that? Kind of a mind fuck isn’t it? Just wondering your opinion. And if your atheist or non-Christian, this obviously isn’t a question directed at you, but feel free to give your opinion.