Marcus Alexander, a 24 year old beefy 6-footer who has been undergoing sex-hormone therapy to become a woman, is charged with sexual abuse of a 4 year old girl for whom he had been babysitting.  The charge carries a penalty of five years to life in jail.  Alexander came to court dressed in a black ribbed skirt, with freshly tweezed eyebrows, manicured nails and a stubbly 5 o'clock shadow.  He had received permission last month from Houston judge Denise Collins to stand trial dressed as a woman.  Prosecutor Cary Hart said the girl's mother will testify that Alexander had his pants down and [her daughter] had her pants down when she returned home on the day of the attack.  Alexander is being housed in the Harris County Jail on a floor reserved for homosexuals.