He Made Them Male and Female

In light of Genesis 5:1-2 we can keep it very simple:

"God created male and female, and blessed them and called them Mankind".

Out of Adam and Eve came every man, woman, and child that has ever been conceived. It was Adam and Eve who carried our seed. It was God who decided the time, date, gender, and location of our birth. In a world where we have very intelligent people articulating they have no idea what a woman or man is, God very clearly has already defined gender. Again it is a very simple process. Right after birth you are assigned your gender in relation to your body parts, in particular your private parts.

One of our inherited sins from our first parents was yielding to the desire to be like God. It used to be that the phrase "You can be anything you want to be" was a good one. It was never meant to indicate we could change the gender God gave us. Pure evil says to thumb your nose at God and show Him you don't have to be what He created you to be. I would only suggest we examine ourselves to see why we think God made a mistake. Sometimes that can involve facing some deep hurts and pain, from both our past and present.

Just in case you think this is somehow a new phenomenon or that's not the Bible has absolutely nothing to say regarding this subject, I would strongly encourage you to visit Romans 1:21-32 remembering all the while it is the sin and the consequences thereafter that God hates, not you. It is always helpful to remember that the Bible is a book that wants to protect us from the evil one and ourselves in that order. There was a reason God told Adam and Eve not to eat from the Tree of Knowledge. He knew we would be here, having this discussion one day.