How and where does the Bible speak to transgender behavior?

Just off the top of my head, Deuteronomy 22:5 comes to my mind.

"A woman shall not wear anything that pertains to a man, nor shall a man put on a woman's garment, for all who do so are an abomination to the LORD your God."

There is something very evil occurring in this world and it is all caused by sin. Some person are bending to these new ways and it is not good. God made male and female and anyone trying to change God's creation is such a manner are playing with fire.

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While it is true that the Bible suggests that we should not cross-dress, let's also remember that the Bible, and all of God's teachings, are about love. We all have people in our lives that believe and think different things, and we are *all* sinners. We need to love the people around us, whether we believe in what they are doing or not. Indeed, Christ asks us to love our enemies, and bless them who persecute us. Let's make sure that we're not using the Bible as an excuse for hatred. That is never what God wants. Let's live the best we know how, and allow others to do the same.

The Christian Post has an article about this, you can read the entire article here:

What Does the Bible Say About Trans-Gender Identity?

Here is the relevant part of the article that directly addresses your question:


Biblical arguments against transgender identity


Robert Gagnon, a scholar who has studied the related issue of the Bible's stance on homosexuality for 15 years, addressed each of Ackley's verses, but began by citing a different verse in 1 Corinthians. He pointed to 1 Corinthians 6:9, where the Apostle Paul includes a group called "malakoi" or "soft men" in a list of those "who will not inherit the kingdom of God."


The professor listed various groups in the ancient Biblical setting who attempted to transform their masculinity into femininity: assinnus, kurgarrûs, or kulu'us; the galli. Deuteronomy 23:18 labels a similar group "an abomination," Gagnon argued, listing other passages which mention these effeminate men (Deut 23:17-18; 1 Kings 14:24; 15:12; 22:46; 2 Kings 23:7; cf. Job 36:14).


Addressing Matthew 19:12, the verse about natural-born eunuchs, the Pittsburgh professor argued that "neither the born-eunuchs nor made-eunuchs have made themselves eunuchs." The only group that voluntarily chooses to be eunuchs "does so only in a metaphorical sense, for they do not mar their body or seek to change their sex in any way." Instead, they merely refrain from sexual relations, which are only licit in a marriage between one man and one woman.


Similarly, "Paul's remark in Gal 3:28 that 'there is no male and female' was applied to the status of women before God, not as a basis for eliminating sexual differentiation or legitimizing attempts to change one's sex," Gagnon wrote. He acknowledged that Jesus taught that there will be no marriage in the kingdom of God, but until that time, sexual activity must only happen in marriage.


Gagnon admitted that, for some people who embrace a gender identity at odds with their birth sex, some parts of the brain may function like the opposite sex. Nevertheless, chromosomes, genitalia, other external features, and hormones all fit one's birth sex, showing God's design.


Transsexuality instead reminded Gagnon of an ancient Christian heresy, Gnosticism, which condemned the material world in favor of the spiritual world. "Attempts to erase one's birth sex have a quasi-gnostic feel: the dominant features of the body do not matter," the Pittsburgh professor wrote. He even hinted that transsexuality may merely be a further expression of homosexuality, which also dishonors the natural sex given by God.


Many will elaborate upon this verse (besides 1 Corinthians 6) forbidding transgendered behavior:


Deuteronomy 22:5 New International Version (NIV)A woman must not wear men’s clothing, nor a man wear women’s clothing, for the Lord your God detests anyone who does this.

God made us male and female - there was no confusion.
With the exception of biological mishaps, this appears to be a psychological problem which needs to be addressed. Medicine can correct physical problems so the person can be whole.

It doesn't really. When the Bible was written, if anyone actually said that they felt like they should be the other sex, they would be thought of as crazy (I'm not saying that's what God thinks). It mentions "effeminate" (like in 1 Corinthians 6:9), but that is usually believed to mean homosexual (gay man). But, when a person feels that they are not the sex which they were born, which sex are they attracted to? That's when it really gets confusing.