I gather that you wish to resolve this with less conflict, so a majority of my arguments are invalid in your case. I lost a sister when I told her I was trans. Her "God" (ahem Priests) tell her to "love the sinner hate the sin", which still has the words "Hate" and "Sin" in it. What I am is not a sin.
You could try something simple, like "No. God made me a woman, and gave me a penis so that I might learn the value of a vagina." but that may start a larger argument.
You could change over to a more lgbt+ friendly brand of religion then let them know your God loves you. Alllll of you.
You could try explaining to them that you have been Called by God to be a woman, because it is the truth.
Yes, I have been called "Confrontational" in the past, which is why none of those lines of reasoning will suit you particularly well.
If you have access to youtube you could try listening to : The Baptist Pastor and His Transgender Friends | Mark Wingfield | TEDxCharlottesville and Why I chose my LGBTQ daughter over the Evangelical Church | Susan Cottrell | TEDxMileHigh. Not knowing if you are being stopped by a person calling themselves Christian, there are other videos about other religions as well.
The sad truth is that convincing a person of faith that their faith is "wrong" about something requires them to have a crisis of faith. It sounds like your parents can either choose to believe you, or what they have been taught.
I choose to believe that God put me here to learn, love, and grow. That means that God will teach, love, and nurture me regardless of my path as long as I do not break the commandments.
Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind. This is the first and great commandment. And the second is like unto it, Thou shalt love thy neighbour as thyself. On these two commandments hang all the law and the prophets.
Matthew 22:35-40 KJV
As their child, are you also not your parents neighbor? That being the case, they should love you as they love themselves without question for all other laws look to these two commandments.
When you are an adult, if you are not already, you (who is made in His own image) will need to make a choice to either be true to yourself and live in the Image God made you (Trans woman), or hide His creation behind the shell of the body you were put in. Both choices are difficult and there is some pain either way. Only one path is honest and comes with peace of mind however.
#Iwontbedeleted
I see you. I accept you. I will pray for you,
Ricki