My denomination, like many, believes when the body dies, but the soul endures. Without a body, what is the force of the argument that a person is merely the sum of their DNA or chromosomes?
Is it possible God can put a girl's soul into a boy's body, or a boy's soul in what outwardly looks like a girl's body? Does He have such power? Is it possible He has a plan that is not known to mere mortals? Is our following His plan a sin? What mortal has the power to know God's plans absolutely?
I am asked: how do you know you are female? I reply: the same way you know when Christ has come into your heart. You don't explain it in terms of learned scientific argument and results from test tubes. You just know. Same way.