HOUSTON --A mother and stepfather are accused of unlawfully engaging in sexual contact with their young son. Martha Ramirez, 43, the boy's biological mother, is charged with indecency with a child. The co-defendant, Gustavo Faz, 54, is charged with aggravated sexual assault with a child. According to court documents, the 11-year-old boy said he was trying to go to sleep in his bedroom on the night of September 1, 2007 when Ramirez pulled down his underwear and put her hand on his penis. The boy, who was 7 years old at the time, told authorities Faz watched the incident from the foot of the bed, then said it was his turn and sexually assaulted the boy. Faz said he had bathed the boy on numerous occasions and had possibly given the boy a suppository, but denied the sexual assault. Ramirez is being held on $20,000 bond. Faz is being held on $30,000 bond.