I lived most of my life being only attracted to female-bodied people... until I realized that I was trans and not just a really butch lesbian. I took a chance and dated an intersexed girl, and while she wasn't quite the right one for me, I had no problem with the fact that she had been born and raised essentially male, and had a penis (though we never had sex). In the 2 months we dated, I noticed she was more feminine than most of the bio females I'd known and dated, and the attraction, physically, was the same. I did wonder if some of that was due to her being intersexed, though; she had latent ovaries and obviously part of her was biologically female.
At the end of that relationship, though, I met my wife, who is a bonafide mtf, and the most beautiful woman I've ever met. I had had very little sexual experience prior to meeting her, and doubted I could ever have sex with someone with a penis, but things do change, and sometimes we're wrong about what we do and don't like. We've been married almost 2 years now, and our sexual relationship is great, despite our parts being incongruent with our genders. I find myself now far more attracted to transwomen than ever before, and I attribute that to my affection toward my wife. People change, and you must remember, it's only a penis. It's just anatomy. A penis makes a woman no less a woman than a vagina makes a man less of a man.