China has selected its second batch of astronauts, including five men and two women, the first time women have joined the country's space mission.

The two women astronauts, both aero-transport pilots from the People's Liberation Army (PLA) Air Force, might take part in manned docking of China's future space lab, said Zhang Jianqi, former deputy commander of the country's manned space program.

"In the selection, we had almost the same requirements on women candidates as those for men, but the only difference was that they must be married, as we believe married women would be more physically and psychologically mature," Zhang said on the sidelines of the annual parliamentary session.

He said women astronauts theoretically enjoy advantages over their male counterparts in terms of endurance and circumspection.

China selected its first batch of 14 astronauts in the middle 1990s. It has sent six astronauts into space since 2003, including astronaut Zhai Zhigang who carried out China's first outer space walk in September 2008.

China plans to launch an unmanned space module in 2011, which is regarded as an essential step toward building a space station.