While not discussed as frequently as male sexual health problems such as erectile dysfunction or premature ejaculation, male infertility is a common problem that causes 20% - 30% of all infertility cases worldwide. Chinese researchers recently carried out an experiment that holds potential for treating this condition: using lab-grown sperm. Taking mouse stem cells, the researchers created primitive sperm which they used to fertilise mice eggs and produce healthy baby mice.
Though this research is in its early stages and has yet to be properly replicated in humans, it could revolutionise male fertility treatments. Male infertility can have several causes, usually centring on testicles (cancer, surgery, birth defects, injury) or sperm (low count, low mobility, abnormal shape). Men who can't produce sperm at all can't have biological children; they must use donor sperm. But if the Chinese experiment can be replicated with human cells, then infertile men may be able to use their stem cells (or potentially their skin cells) to create sperm and have biological children. This would be a massive development in fertility treatments.
While people may think that men create millions of sperm in no time and with little effort, making sperm in the testes is actually a long and complex process. It can take between two and three months for sperm to fully mature. One of the main causes of male infertility is a lack of meiosis – the process of germ cells rearranging their DNA to become sperm cells. But using a combination of chemicals, hormones and testicular tissue, the Chinese researchers were able to recreate meiosis in the lab, achieving the international gold standard that has been set for that difficult procedure.
First, the researchers took embryonic stem cells from mice, and used chemicals to transform them into germ cells – cells which can only become sperm or eggs. They then turned the germ cells into sperm by exposing them to testosterone and testicular cells. Instead of creating fully developed sperm, they created spermatids –essentially baby sperm, without a tail and an oval head. The spermatids were developed enough to impregnate mouse eggs through in-vitro fertilisation. The mice gave birth to healthy babies. Those babies then grew up and had babies of their own, showing that lab-grown sperm were capable of creating a successful reproductive cycle.
Several UK fertility professors have expressed excitement at the future possibilities of this research, but also raised practical and ethical concerns. They commented on the hope this could bring infertile men and the incredible scientific advancement it would represent. Advising typical scientific caution, however, they noted that this procedure would be very difficult to replicate with human sperm and that couple's currently facing male infertility shouldn't expect viable treatments anytime soon.
They also noted the very real ethical debate that could arise using sperm made in a lab to create a human life. British fertility clinics are currently banned from using artificial sperm or eggs to treat infertile couples; a change in government policy would be required and a public discussion would likely ensue.
Lab-grown sperm is a long way off – scientifically and ethically – from being commonly used in human fertility treatments. However, this research shows that it may be possible, which could change the entire landscape of fertility treatments.