A change of law has paved the way for more babies to be born from sperm frozen up to 50 years ago, but experts say there is no scientific reason why sperm hundreds of years old cannot be used.

This week, a boy was born using sperm frozen in 1996, collected when his father was diagnosed, aged 21, with Hodgkin lymphoma, in case his treatment caused infertility.

Described as a “miracle” by his now 47-year-old father, Peter Hickles, the baby is close to holding the record for the longest gap between sperm collection and birth – he was beaten by a baby born in the US using a 27-year-old sample.

When Hickles’ sperm was frozen, he thought it would only be viable for 10 years. Although experts say the technology for freezing sperm has been around for decades, prior to a law change in the summer, gametes (eggs and sperm) could only be stored for 10 years, with occasional exceptions made for people with fertility problems.

This has now been extended to 55 years, but Allan Pacey, a professor of andrology at the University of Sheffield, said there was no medical reason for this limit.

“The legal 55-year limit has nothing to do with the shelf life of sperm, or for any other scientific reasons. It’s more to do with what parliamentarians felt was right for society. But since frozen sperm are effectively in suspended animation, once they are frozen I don’t see why they couldn’t be kept for hundreds of years if the law allowed it.”

He said there were not believed to be any health risks from using older sperm, though there were no long-term studies outside the cattle breeding industry. “Sperm from prize bulls [is] kept in storage for much longer than we typically keep human sperm for, without any obvious problem,” he said.

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Without evidence of likely harm, such studies would struggle to receive funding, he said, and they would need to be on a global scale because cases like that of Hickles were still rare.

While conserving sperm for decades could theoretically enable children to be born from historical figures, this would not be possible in the UK at present, where the law prevents the creation of a sperm market and limits its use to 10 families per donor. Allan also questioned the likelihood of such a scheme’s success: the world’s first Nobel prize-winner sperm bank closed due to limited demand.

Dr Lucy Frith, a bioethicist at the University of Manchester, said the law change could result in “generational discrepancies”, where a younger sibling is born from sperm older than that of their siblings, with whom they might have a 40-year age gap. If the sperm was donated, children may try to look for biological fathers who were elderly or had died by the time of the child’s 18th birthday.

Julian Savulescu, an ethics professor at the University of Oxford, said long-term wellbeing studies were needed if the use of older sperm was to become more common, including on the emotional impact of having a dead biological father, and on general health.

“We’re really doing an experiment, and I’m in favour of those, but you have a moral obligation to generate knowledge and modify practice according to the results,” Savulescu said.

If very old sperm was used, for example, from 250 years previously, this could raise ethical questions, he said, because society and people’s genomes may have changed radically. Although these remained “science fiction worries” given sperm freezing only began in the 1950s, he added.

In the meantime, old sperm provides an opportunity for people who might not otherwise have been able to have a family to become parents.

Hickles, a football fan and former Spurs youth player, has his own way of measuring the gap between his sperm and the birth: “I keep looking at him, shaking my head in disbelief. He really is a little miracle. The fact that he was basically ready to go just before Euro 96 and was born before the World Cup is amazing.”