Will lab-grown sperm let infertile men have children of their own?

Coloured scanning electron micrograph of human sperm cells Infertility isn’t something men like to talk about but it’s very common. Around 1 in 10 couples will have problems with conception, and in half of cases it is wholly or partly to do with sperm . In many cases, existing fertility treatments can’t help – but a US start-up called Paterna Biosciences thinks it can change this.

Paterna claims that it can take stem cells from the testes and turn them into sperm cells in the lab. What’s more, the company says this technique could enable almost all the men for whom fertility treatments currently fail to father children of their own. But others in the field think it could be of very limited use for treating male infertility – unless it’s combined with CRISPR gene editing. That’s right, I’m talking about creating gene-edited children. There are a huge range of reasons why men may struggle to father a child. They may have a low sperm count, their sperm may not be good swimmers or may lack the ability to enter the egg, and so on. In these kinds of cases, injecting a sperm directly into an egg – intracytoplasmic sperm injection, or ICSI – as part of IVF treatment usually works. Around 1 in 100 men don’t have any sperm at all in their semen. (This often-cited number is from an old paper, by the way, and could well be higher now, given the apparent decline in male fertility – but that’s another story.) This lack of sperm can be because some kind of obstruction is preventing the sperm from reaching the prostate. In these cases, it is usually possible to remove the obstruction or take sperm directly from testes. But in most cases where there are no sperm in semen, it is because very few or none are being produced in the testes. That’s where Paterna Biosciences comes in.

Key points

• Paterna claims that it can take stem cells from the testes and turn them into sperm cells in the lab.
• What’s more, the company says this technique could enable almost all the men for whom fertility treatments currently fail to father children of their own.
• But others in the field think it could be of very limited use for treating male infertility – unless it’s combined with CRISPR gene editing.
• That’s right, I’m talking about creating gene-edited children.
• There are a huge range of reasons why men may struggle to father a child.