I apologize for having come into this conversation late.
While it is true that every so often, someone is born with strange or unnatural contortions of genitalia, I believe that we ought to follow the gender that we were born with, or in these cases, the majority gender.
"So God created man in his own image, in the image of God he created him; male and female he created them." Genesis 1:27 ESV
"He answered, Have you not read that he who created them from the beginning made them male and female," Matthew 19:4 ESV
Personally, I believe that transsexual, or males who identify as women go against the way God intended them to be, and as such, sin against his will.
However, I wish to point out that this does not give us Christians leeway to condemn them for their actions.
Jesus tells us to love. So I will love my neighbor.
However, if a transgendered or transsexual individual by the power of the Spirit seeks out the Kingdom of Heaven, and Christ, there MUST come a time when he/she/it is informed of [their] sinfulness. If he/she/it seeks to remain in sin without turning and repenting, well, then we must wipe the dust off our feet (Matthew 10:14-15).
We should not condemn, but love, and if Christ is sought, gently rebuke and forgive.
"For all have sinned and fall short of the glory of God" Romans 3:23 ESV
"As it is written: There is no one righteous, not even one; there is no one who understands; there is no one who seeks God. All have turned away, they have together become worthless; there is no one who does good, not even one. Romans 3:10-12
Transgendered/transsexual individuals must repent of their iniquities, much as I must. I am no better than them, and they are no better than me.
We are all equally unworthy in the eyes of God, but made worthy in the suffering and pain of our Lord Jesus on the Cross, and in His glorious Resurrection three days late.