No humans have yet set foot on the Red Planet, but Elon Musk estimates that a million people will live on the planet by 2050.

The boss of SpaceX and Tesla plans to send a small group of astronauts to Mars by the end of this decade aboard his Starship, the largest rocket ever built.

Ultimately, a colony of men and women will reproduce there to increase the Martian population, the billionaire hopes.

But scientists say the difficulties of having sex on Mars make this highly unlikely, if not impossible.

Kelly Weinersmith, a bioscientist and author based in Charlottesville, Virginia, says people who want to populate Mars “don’t understand how reproduction works.”

Weinersmith, who wrote the 2023 book “A City on Mars” with her husband Zac, told the Times: “These billionaires think it’s an engineering problem.

“They think if they get a big enough rocket the biology will take care of itself, but that’s not the case.”

Couples could be putting the health of their unborn babies at risk by conceiving in space, whether they’re on Mars or orbiting Earth aboard the ISS.

Ultimately, a colony of men and women will reproduce on Mars to increase the human population there, hopes Elon Musk. But scientists say the difficulties of having sex on Mars make this highly unlikely, if not impossible. Pictured is an AI impression of mating on Mars

“A City on Mars” – illustrated by Kelly’s husband Zach – won the Royal Society’s prestigious Trivedi Science Book Prize last week.

In the book, the duo tackles the difficult logistics of recreational and procreative sex on Mars, as well as masturbation.

On the Martian surface, gravity is about 38% that of Earth, so this low-gravity environment could hinder embryo development or sperm movement.

Meanwhile, Mars’ lack of an atmosphere and ozone layer, like Earth’s, means harmful radiation rays hit the rusty surface.

Conception could lead to harmful effects of radiation on an embryo, including possible DNA damage that could cause mutations in the womb.

Additionally, even if sex on Mars leads to a successful birth, the taxing atmosphere on Mars is arguably no place for a child.

Raising children like Martians is perhaps one of the most important problems, fraught with ethical and practical implications.

According to Kelly and Zac, even if problems related to sex and conception in space were avoided, another problem would be getting enough genetic diversity in a Martian population.

Mars is the fourth planet from the Sun – a desert world, dusty and cold, with a thin atmosphere. In the photo, Mars captured by the Hubble telescope

Elon Musk believes he can send crewed flights to Mars as early as the second half of this decade. The problem is that conditions on Mars could seriously damage multiple body parts, accelerating disease and death – even with a spacesuit.

A founding population should consist of several hundred humans before they start mating, and even then they should mate with the “right people”.

A computer program or AI would potentially need to compile genetic information on all space travelers before matching couples in order to maintain high genetic diversity.

“It works if we all do what the computer says and no one dies,” Zac says.

David Cullen, professor of astrobiology at Cranfield University, said there remained “unanswered biological and legal questions” regarding sex in space that needed to be “urgently resolved”.

He thinks the key problem with sex on Mars would be the effect of changing gravity, but there has been a lack of studies to “clearly understand what the consequences might be.”

Professor Cullen told MailOnline: ‘A more obvious question concerns later stages of the full human life cycle, such as the effect of reduced gravity on the development of the musculoskeletal system after childbirth, childhood and adolescent development.

“We know that there is a dynamic effect of the gravitational environment and therefore a load on the musculoskeletal system, which affects the development of the musculoskeletal system.”

Professor Cullen added that conception could potentially occur during sex on Mars, but the “subtle developmental risks” throughout a human’s life cycle are unknown.

With Starship, Musk could realize his grand ambition of transporting people and cargo to the Moon and eventually Mars, making us a “multi-planetary” species. Pictured, Starship prototype in August 2021

In 2017, Musk said SpaceX would launch its first cargo missions to Mars in 2022 and the first crews to the planet in 2024.

Professional astronauts may not admit to making sex their top priority when setting up infrastructure on Mars as part of SpaceX’s big plans, although human nature will surely come into play sooner rather than later.

Musk recently said SpaceX will send its multibillion-dollar Starship rocket to Mars in 2026, although it will be an uncrewed mission.

Two years later, in 2028, Starship will transport people to Mars for the first time – which would mark the first time humans have walked on another planet.

Ultimately, Musk wants to make humans a “multi-planetary” species, meaning we live on multiple planets, not just Earth.

Musk believes a natural or man-made disaster will eventually result in the end of civilization, necessitating relocation to another planet – with Mars being “the only realistic option.”

It could be a pandemic worse than Covid, a continued decline in birth rates, a nuclear Armageddon or perhaps a direct hit from a killer comet “that would wipe out a continent” .

His highly entertaining research article published in New Space, titled “Making Humans a Multi-Planetary Species,” describes the company’s vision.

“History is going to bifurcate in two directions: on the one hand, we will stay on Earth forever and then there will be a possible extinction event,” he says.

“The alternative is to become a space-faring civilization and a multi-planetary species, which I hope you agree is the right path to take.”