Feeling like you are the opposite gender is not the same as being attracted to the same gender. Gender identity and gender attraction are separate. David Reimer, an unfortunate young man whose penis was cut off in a circumcision accident (don’t get me started on circumcision!) after which his parents were advised to raise him as a girl, which turned into an unmitigated disaster. According to him, from his earliest memories, he felt like he was a boy. Unfortunately he eventually committed suicide.
http://open.salon.com/blog/xylocopa/2011/01/11/in_memory_of_david_reimer_1