Scientists are making significant strides in creating viable human sperm and eggs in the laboratory, particularly through advancements in in-vitro gametogenesis (IVG), as highlighted by Prof Katsuhiko Hayashi from the University of Osaka.

Hayashi estimates that his lab could achieve this milestone within approximately seven years, with other research teams, including those at the University of Kyoto and Conception Biosciences in California, also making rapid progress.

Recent breakthroughs include the successful creation of mouse sperm cells and human ovary organoids, which indicate promising developments towards the cultivation of human eggs.

While there have been successful instances of reproducing baby mice from lab-grown eggs, the challenge of creating viable human eggs remains, though recent insights into egg dormancy may prove crucial.

The IVG process involves reprogramming adult skin or blood cells into stem cells, which are then developed into primordial germ cells and placed into lab-grown organoids to mature into eggs or sperm.

Despite the excitement surrounding this technology, there are significant safety concerns, particularly regarding the risk of genetic mutations in lab-grown cells and the potential implications for future generations.

In the UK, current laws prohibit the use of lab-grown cells in fertility treatments, prompting the Human Fertilisation and Embryology Authority to investigate safety concerns and establish necessary testing protocols.

Conception Biosciences, supported by notable figures such as Sam Altman, aims to develop lab-produced eggs to address population decline and facilitate human gene editing.

The possibility of unconventional reproductive concepts, such as unibabies (single-parent genetic contributions) or multiplex babies (multiple genetic contributions), raises important ethical questions that necessitate careful regulation.

Experts like Prof Rod Mitchell from the University of Edinburgh and Prof Allan Pacey from the University of Manchester endorse Hayashi's timeline, suggesting that generating human eggs or sperm from immature cells could be feasible within five to ten years.

Hayashi expresses caution regarding the applications of this technology, particularly for older women or same-sex couples, due to safety risks, while acknowledging that societal acceptance could play a role in its future use.