Space travel has become a reality, especially with wealthy people planning to build luxury hotels on the moon. But there is an unexplored aspect of this type of adventure, which is its potential impact on the ability to reproduce.
A comprehensive study published in the online journal Reproductive Biomedicine reviewed decades of research on the impact of space on human fertility, and its results raise concern for anyone who would like to undergo this experience.
Threat to fertility
Cosmic radiation may destroy the DNA in eggs and sperm, and weightlessness may disturb the hormonal balance necessary to regulate the reproductive process.
Even the stress and sleep disturbances that accompany space travel can negatively affect reproductive functions.
Moreover, space tourists are not subject to careful medical examinations and constant follow-up as is the case with NASA astronauts.
There are no binding passenger safety standards that address reproductive risks, no mandatory health warnings, and no uniform protocols about what companies must disclose.
Researchers warn that as commercial spaceflight takes off without clear standards for reproductive safety, profit motives can override medical caution.
Researchers warn that as commercial spaceflight takes off without clear standards for reproductive safety, profit motives can override medical caution.
The radiation problem that everyone ignores
On our planet, the magnetic field protects us from the harmful effects of space radiation. But this protection disappears once you leave the atmosphere. Astronauts on the International Space Station are exposed to approximately 0.5 millisieverts per day, which is much higher than the normal rate on Earth.
During a round trip to Mars, travelers will be exposed to approximately 662 millisieverts of cumulative radiation: levels that are within the ranges known through medical research to be threatening to reproductive tissue.
*Women face particularly high risks. Medical evidence from radiotherapy for cancer suggests that radiation doses as low as 2 Gy can destroy half of a woman’s egg reserve. The same biological vulnerability applies in space. High doses can lead to early menopause.
*Men are not immune to this either. While sperm may retain their motility after exposure to radiation in space, studies show DNA damage and impaired maturation that could affect future children. Doses above 250 mGy can lead to a permanent decrease in sperm count.
Scientists have tried to culture mouse embryos on spacecraft, with disturbing results. In a Chinese trial, embryos cultured in orbit for only 64 hours showed severe DNA damage and abnormal development. While most embryos successfully divided into cells in the early stages, their rate of development into blastocysts (the stage necessary for pregnancy) dropped from about 60% on Earth to only 34% in space.
