Sperm get lost in space, Australian research into microgravity impacts suggests

## Summary
Photograph: Sperm and Embryo Biology Laboratory, Adelaide University View image in fullscreen An Adelaide University study has found the navigational abilities of sperm are negatively impacted by a lack of gravity. Photograph: Sperm and Embryo Biology Laboratory, Adelaide University Sperm get lost in space, Australian research into microgravity impacts suggests Study into how fertilisation could work in space finds sperm may get disorientated when trying to find an egg Sperm in space are likely to get disoriented and lost while struggling to find their way to an egg, a new study has found. When exposed to microgravity in experiments, sperm tumble around like an untethered astronaut, according to Adelaide University researchers. “It causes them to flip around, to go upside down … they don’t really know which way is up or down,” researcher Dr Nicole McPherson said. Photograph: Sperm and Embryo Biology Laboratory, Adelaide University “We’re interested in not only understanding the effects of zero g, but also those varying gravitational forces, things that we might see on the moon or Mars, because we do know that there is a long-term plan for humans to have settlements there. “While it may seem like a bit of sci-fi … we’re actually gaining fundamental knowledge in how sperm navigate and transverse the female reproductive tract.” The researchers collaborated with the university’s Andy Thomas Centre for Space Resources. “As we progress toward becoming a spacefaring or multi-planetary species, understanding how microgravity affects the earliest stages of reproduction is critical,” said the centre’s director, associate professor John Culton.

## Article Content
An Adelaide University study has found the navigational abilities of sperm are negatively impacted by a lack of gravity.
Photograph: Sperm and Embryo Biology Laboratory, Adelaide University
View image in fullscreen
An Adelaide University study has found the navigational abilities of sperm are negatively impacted by a lack of gravity.
Photograph: Sperm and Embryo Biology Laboratory, Adelaide University
Sperm get lost in space, Australian research into microgravity impacts suggests
Study into how fertilisation could work in space finds sperm may get disorientated when trying to find an egg
Sperm in space are likely to get disoriented and lost while struggling to find their way to an egg, a new study has found.
When exposed to microgravity in experiments, sperm tumble around like an untethered astronaut, according to Adelaide University researchers.
“It causes them to flip around, to go upside down … they don’t really know which way is up or down,” researcher Dr Nicole McPherson said.
More frequent ejaculations may boost men’s fertility, research suggests
Read more
Australia is part of
Nasa’s planned Artemis mission
to go to the moon and on to Mars, while private companies including
Elon Musk’s SpaceX plan
to build human habitats on Mars. As a result there has been increasing interest in how humans might reproduce and breed animals in extraterrestrial habitats.
The Adelaide researchers used a machine to mimic microgravity – the same sort of freefall or weightlessness astronauts on the International
Space
Station experience. The clinostat “causes cells to not really understand or know which direction they’re going in”, McPherson said.
“With the recent advancements in space travel and international interest in deep space exploration, Mars settlement and moon mining, it is critical to investigate the effect of microgravity on early fertilisation events not only for creating viable food sources, but also maintaining human space settlements, without the need to continually re-populate from Earth,” they noted in an article published in the journal
Communications Biology
.
McPherson said the microgravity research also benefits earthly reproductive science.
The researchers, from the university’s Robinson Research Institute, used sperm samples from humans, mice and pigs.
They put them in a 3D clinostat machine, which spins around to negate the effect of gravity, then in a maze that was a simulation of the female reproductive tract – although in the case of human sperm, no egg was placed at the end of it due to ethical reasons.
The sperm exposed to microgravity struggled to find their way through the maze, they found.
There was about a 40% reduction in the number of microgravity-exposed human sperm that made it through compared with the control group.
Microgravity also affected how pig and mouse embryos developed.
McPherson, the senior author, said it was the first time they had shown that gravity was an important factor in sperm’s navigational ability, and that while it had a negative effect, healthy embryos were still able to form.
“This gives us hope that reproducing in space may one day be possible,” she said.
Exposure to zero gravity appeared to modify the number of foetal cells within the embryo.
Photograph: Sperm and Embryo Biology Laboratory, Adelaide University
“We’re interested in not only understanding the effects of zero g, but also those varying gravitational forces, things that we might see on the moon or Mars, because we do know that there is a long-term plan for humans to have settlements there.
“While it may seem like a bit of sci-fi … we’re actually gaining fundamental knowledge in how sperm navigate and transverse the female reproductive tract.”
The researchers collaborated with the university’s Andy Thomas Centre for Space Resources.
“As we progress toward becoming a spacefaring or multi-planetary species, understanding how microgravity affects the earliest stages of reproduction is critical,” said the centre’s director, associate professor John Culton.
Adding progesterone helped overcome the sperms’ disorientation, which researchers think is because eggs also release it and it can help guide the sperm.
McPherson said radiation, which bombards astronauts as they leave Earth’s protective atmosphere, also affects sperm.
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There is a long history of studying reproduction in space.
The Adelaide University article points to an 1987 investigation on Cosmos 1887, which found “space-exposed rats had reduced testicular mass”, and experiments on mouse embryos on the Columbia space shuttle in 1998.
In 2018 Nasa sent human sperm on the mission Micro-11 to the ISS to study the effects of weightlessness. The US space agency also runs an ongoing developmental, reproductive and evolutionary biology program.
In 2024, the New York Times reported that Musk had volunteered his sperm to help seed a colony on Mars, a claim he has denied.
In Februar

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## Expert Analysis

### Merits
- McPherson, the senior author, said it was the first time they had shown that gravity was an important factor in sperm’s navigational ability, and that while it had a negative effect, healthy embryos were still able to form. “This gives us hope that reproducing in space may one day be possible,” she said.
- Photograph: Sperm and Embryo Biology Laboratory, Adelaide University “We’re interested in not only understanding the effects of zero g, but also those varying gravitational forces, things that we might see on the moon or Mars, because we do know that there is a long-term plan for humans to have settlements there. “While it may seem like a bit of sci-fi … we’re actually gaining fundamental knowledge in how sperm navigate and transverse the female reproductive tract.” The researchers collaborated with the university’s Andy Thomas Centre for Space Resources. “As we progress toward becoming a spacefaring or multi-planetary species, understanding how microgravity affects the earliest stages of reproduction is critical,” said the centre’s director, associate professor John Culton.

### Areas for Consideration
N/A

### Implications
- Photograph: Sperm and Embryo Biology Laboratory, Adelaide University Sperm get lost in space, Australian research into microgravity impacts suggests Study into how fertilisation could work in space finds sperm may get disorientated when trying to find an egg Sperm in space are likely to get disoriented and lost while struggling to find their way to an egg, a new study has found.
- More frequent ejaculations may boost men’s fertility, research suggests Read more Australia is part of Nasa’s planned Artemis mission to go to the moon and on to Mars, while private companies including Elon Musk’s SpaceX plan to build human habitats on Mars.
- As a result there has been increasing interest in how humans might reproduce and breed animals in extraterrestrial habitats.
- McPherson, the senior author, said it was the first time they had shown that gravity was an important factor in sperm’s navigational ability, and that while it had a negative effect, healthy embryos were still able to form. “This gives us hope that reproducing in space may one day be possible,” she said.

### Expert Commentary
This article covers sperm, space, microgravity topics. Notable strengths include discussion of sperm. Readability: Flesch-Kincaid grade 0.0. Word count: 830.