Do you have selfish sperm? We asked experts what this means and how it might be impacting your future offspring
Ever heard of selfish sperm? Well – it’s a real thing – and despite how it sounds, it’s not a dis to your downstairs; it actually relates to the genetic behaviour of sperm in older men.
“Many men are not always aware of how age and overall health can influence fertility. If fatherhood is something they are considering later in life, it’s important to approach that decision with some forward planning.”
That’s what Dr Victoria Sephton says. She’s the Chief Medical Officer at Care Fertility. But what exactly does the term ‘selfish sperm’ mean? And should it affect our fertility choices? We got the lowdown from Dr Sephton on whether we should be concerned.
So, what is selfish sperm?
Selfish sperm is sperm that carries a higher rate of genetic mutation, which increases the risk of neurological conditions and cancers in future offspring. These mutations occur via the process of selfish spermatogonial selection, where the rate at which sperm mutates increases exponentially. This means as men age, the likelihood of mutations on health affecting genes increases. All sperm mutates, but selfish sperm carries mutations on these important genes. Complicated right? But concerning? Yes.
Does sperm really decline with age? And if so why?
“Yes, sperm quality can change gradually over time,” says Dr Sephton. “We may see differences in sperm count and movement, as well as an increase in DNA fragmentation as men get older. In some cases, higher levels of DNA damage can mean it takes longer to achieve a pregnancy and may slightly increase the risk of miscarriage.”
However – that’s not the only consideration men should make when thinking about having children, says Sephton. “Weight, metabolic health, smoking, alcohol intake, stress and sleep all influence sperm health. Many of these lifestyle factors are within a man’s control, which means there are practical steps that can be taken to support fertility when planning for a family.”
Should this research affect our fertility choices?
The research around selfish sperm behaviours boosts our understanding of men’s fertility – and isn’t designed to scare us, says Sephton. “It is not intended to create alarm. While studies do show a potential increase in certain risks as paternal age rises, the overall likelihood of a healthy pregnancy and child remains possible. In practical terms, the increase in risk is small.”
“This research adds to our understanding of male reproductive biology and helps us have more open, balanced conversations about paternal age,” she says, suggesting that there can even be some positives to be gained. “Having open, evidence-based conversations allows both partners to feel informed and involved. It moves the focus away from pressure on one person and towards shared understanding and thoughtful planning together.”
Is there anything you can do if you’re worried?
“For some men, freezing sperm at a younger age may also be a conversation worth having with a specialist,” suggests Sephton. “Taking time to consider these options early can help couples feel more informed and better prepared when they decide the time is right to start a family.”
Lifestyle factors should also be considered – and that may mean cutting down on the booze and sugar unfortunately. “Paying attention to weight, nutrition, exercise and the management of any underlying medical conditions can all play a role in supporting sperm health,” says Sephton. “A fertility assessment can offer reassurance or highlight areas where health could be optimised.”
“The most important takeaway is awareness. When couples have clear, evidence-based information, they are better placed to make decisions that align with their family plans and their long-term health.”
