The "girl"  (Gwen/Eddie Araujo) you are refering to was not a transsexual, but a transgender person who presented as a female.  She/he was not on female hormones, and as a result, had no female secondary sexual characteristics (female breasts, softer skin female-pattern body hair, female body-fat distribution).  She/he was a boy who eiether liked dressing like a girl, or possibly couldn't afford hormone replacemant therapy.  And no, being with a transsexual woman doesn't make you gay.  By definition a gay guy is a male who enjoys sexual relations with a male who looks, dresses, and acts like a male.  You may be classified as "Queer" in many circles, but you are definately not gay.