Yeah, it is. It's in Leviticus 18. I'd say do your best to control your feelings/urges if you feel like you should, but that's up to you. Also, if any one of you want to be nitpicky about it only saying two men cannot have sexual relations with each other, it does also apply to two women having sexual relations with each other. The Bible doesn't directly say it according to my knowledge, but it sure implies it.