NASA is sending sperm cells into space in the hopes to investigate whether a conception of a human life is possible in a zero-gravity environment.
The American space agency is moving one step forward in space exploration as the Micro-11 mission carries frozen human and bull sperms aboard the SpaceX Falcon 9.
In a statement, NASA said the scientists are studying the effects of weightlessness on the sperms' ability to fertilize the egg, which is a crucial stage in conception.
"Previous experiments with sea urchin and bull sperm suggest that activating movement happens more quickly in microgravity, while the steps leading up to fusion happen more slowly, or not at all. Delays or problems at this stage could prevent fertilization from happening in space," NASA wrote.
Joseph Tash, a researcher at the University of Kansas Medical Center, said studies on fertilization and conception in space is part of NASA's plan to travel broadly and longer in search for a new potential habitat.
While the Russian cosmonauts have successfully sent a pair of male and female rats into space in 1979, the mission did not result in any babies. It is still unknown how the absence of gravity in space would impact fertilization as well as the conception of an unborn child.
The Spatial Effect
A study, which was published in the Journal of Women's Health in 2014, identified radiation, microgravity, and stress as major influences on a person's reproductive processes.
Dr. Ellen Baker, a physician and an astronaut herself who serves as the Chief of the Education and Medical Branch of NASA, reported that orbiting the Earth would expose a person to 54 to 108 mSv of radiation. A travel to Mars's surface would prolong and increase the exposure level, not calculating other factors like solar activities and ISS altitude.
Prolonged exposure to radiation increases the risk of cancer that is found to be more age-dependent and gender-dependent in space. Women become at risk of breast, ovarian, thyroid, and lung cancers, and they require shorter space duration to stay healthy.
Baker said that extended travel from six to 12 months could affect men's production of sperm and women's ovulation cycle.
"Longer duration missions, spanning multiple reproductive cycles in both men and women, raise a significant knowledge gap concerning the impact of long-term spaceflight on reproductive health," Baker explained.
Microgravity or the presence of weak gravity while orbiting in spacecraft can induce stress in animals and human beings. Baker cited a Russian study where participants had 120-day bed rest. Samples of sperm were collected in a period of 50 to 60 days and after 100 days of stay in a simulated space shuttle.
Researchers observed that the samples had a reduction in the number of live spermatozoa as well as an increase in the number of altered spermatozoa. Sleep disruption, which is usual in space flight, also induces stress affecting the reproductive health system over an extended period of time.
Effects of microgravity on estrogen level in space are understudied. Astronauts are advised to take oral contraceptives to reduce the release of oxytocin, a hormone responsible for social interaction and sexual reproduction.
Flight doctors recommend female astronauts to take 30 to 35 milligrams of oral contraceptives per day for the suppression of the ovary and reduce chances of bone loss. However, NASA said oral contraceptives are not required. It is also notable that so far, no study has indicated that oral contraception aid stress responsiveness in space flights.
In 2010, researcher Helder Marcal, from the University of New South Wales in Australia, said microgravity-simulated experiments did not yield positive results in favor of human health. Marcal said that the ability of a developing embryo to adapt in space environments is different than that of an adult.
She added that there is reasonable doubt to say that such experience would be perilous to a fetus, although further scientific research is warranted.