Frozen sperm retains viability in outer space conditions: Study

The human sperm retains its complete viability within the different gravitational conditions found in outer space, a study has found. The research opens the possibility of safely transporting male gametes to space and creating a human sperm bank outside Earth.

Scientists from Polytechnic University of Barcelona in Spain said that there is lack of difference in a range of sperm characteristics observed in frozen sperm samples exposed to microgravity and those maintained in ground conditions.

While the effects of microgravity on the cardiovascular, musculo-skeletal and central nervous systems are well known and tested in space flight, relatively little is known about the effects of different gravitational environments on human sperm and eggs.

“Some studies suggest a significant decrease in the motility of human fresh sperm samples, but nothing has been reported on the possible effects of gravitational differences on frozen human gametes, in which state they would be transported from Earth to space,” said Montserrat Boada from Dexeus Women’s Health in Barcelona.

The study was performed using a small aerobatic training aircraft (CAP10), which can provide short-duration hypogravity exposure.

The plane executed a series of 20 parabolic manoeuvres, providing 8 seconds of microgravity for each parabola.

Overall, ten sperm samples obtained from ten healthy donors were analysed after exposure to the different microgravities found in space and ground gravity.

The sperm analysis comprised a full range of measurements currently performed for fertility testing—concentration, motility, vitality, morphology and DNA fragmentation.

Researchers found no difference whatsoever in any of the parameters between the microgravity space samples and the control group samples from Earth.

The team will now try to validate the results with larger sperm samples, longer periods of microgravity and even fresh sperm.

“If the number of space missions increases in the coming years, and are of longer duration, it is important to study the effects of long-term human exposure to space in order to face them,” said Boada.

“It is not unreasonable to start thinking about the possibility of reproduction beyond the Earth,” she said.