Dr. Rachel Armstrong, a British Interplanetary, stated that the US was considering chemical sterilization of astronauts on longer journeys. They are considering ways to curb natural urges on future trips to Mars, which would last 3 yrs. or more.
Dr. Armstrong said talk was going on to discuss the problems that humanity may face in trying to reach planets and eventually even reaching the stars. Suggestions of long-range trips was announced by President Bush in January.
NASA's Johnson Space Center said they knew nothing of the talks. This denial may stem from the fact people may not want to discuss the delicate subject of sex in space after the uprising caused by the Super Bowl nipple baring incident. Source