That depends on your definitions. Yes, a man or woman certainly might struggle with homosexual temptations and even behavior, yet truly be a Christian. However, if someone pursues homosexual involvement and refuses to acknowledge this as sin, it's valid to humbly question whether their commitment to Christ is genuine.

Some professing Christians tout a "pro-gay theology" which alleges that Scripture has been mistranslated and misinterpreted when it comes to the issue of homosexuality. All prohibitions against homosexual behavior are explained away. Sometimes, same-sex friendships between Bible characters (Jonathan and David; Ruth and Naomi) are said to be model homosexual relationships. This deceptive, seductive, self-justifying theology constitutes Scripture twisting (see 2 Corinthians 4:2).

(Exodus International)