Romans and other Paul writings are in the New Testament.
If you're referring to Leviticus 18:22, that's a mistranslation, or misinterpretation.
The quote translates more accurately to "Man must not lie with male...," not "Man must not lie with man."
"Man" would be an adult male. "Male" would be a male who is not yet an adult. So it actually means an adult man should not lay with a male who is not an adult yet.
There's even the claim that it goes further still, that it actually translates into man not laying with a young male of his own family, so the prohibition is against incest.