I'm not a Christian and reject the divinity of Christ, but:
There is neither Jew nor Gentile, neither slave nor free, nor is there male and female, for you are all one in Christ Jesus.
from Galatians 3:28
Not sure how conservative Christians rationalize this part of the Bible, have actually been keen to discuss it with someone.
I mean, Paul, the author of Galatians, also said it was preferable to not marry, that it's best to not have sex (and thus not have children), probably because in his mind the apocalypse was supposed to be right around the corner. Meanwhile, the Christian Right generally supports a Quiverfull approach to breeding (Genesis 1:28: "Be fruitful and multiply" being taken a bit literally).