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We hear a lot about women’s biological clock and how age affects the chance of pregnancy.

New research shows men’s fertility is also affected by age. When dads are over 50, the risk of pregnancy complications increases.

Data from more than 46 million births in the United States between 2011 and 2022 compared fathers in their 30s with fathers in their 50s.

While taking into account the age of the mother and other factors known to affect pregnancy outcomes, the researchers found every ten-year increase in paternal age was linked to more complications.

The researchers found that compared to couples where the father was aged 30–39, for couples where the dad was in his 50s, there was a:

• 16% increased risk of preterm birth
• 14% increased risk of low birth weight
• 13% increase in gestational diabetes.

The older fathers were also twice as likely to have used assisted reproductive technology, including IVF, to conceive than their younger counterparts.

Dads are getting older

In this US study, the mean age of all fathers increased from 30.8 years in 2011 to 32.1 years in 2022.

In that same period, the proportion of men aged 50 years or older fathering a child increased from 1.1% to 1.3%.

We don’t know the proportion of men over 50 years who father children in Australia, but data shows the average age of fathers has increased.

In 1975 the median age of Australian dads was 28.6 years. This jumped to 33.7 years in 2022.

How male age affects getting pregnant

As we know from media reports of celebrity dads, men produce sperm from puberty throughout life and can father children well into old age.

However, there is a noticeable decline in sperm quality from about age 40.

Female partners of older men take longer to achieve pregnancy than those with younger partners.

A study of the effect of male age on time to pregnancy showed women with male partners aged 45 or older were almost five times more likely to take more than a year to conceive compared to those with partners aged 25 or under. More than three quarters (76.8%) of men under the age of 25 years impregnated their female partners within six months, compared with just over half (52.9%) of men over the age of 45.

Pooled data from ten studies showed that partners of older men are also more likely to experience miscarriage. Compared to couples where the male was aged 25 to 29 years, paternal age over 45 years increased the risk of miscarriage by 43%.

Older men are more likely to need IVF

Outcomes of assisted reproductive technology, such as IVF, are also influenced by the age of the male partner.

A review of studies in couples using assisted reproductive technologies found paternal age under 40 years reduced the risk of miscarriage by about 25% compared to couples with men aged over 40.

Having a male under 40 years also almost doubled the chance of a live birth per treatment cycle. With a man over 40, 17.6% of treatment rounds resulted in a live birth, compared to 28.4% when the male was under 40.

How does male age affect the health outcomes of children?

As a result of age-related changes in sperm DNA, the children of older fathers have increased risk of a number of conditions. Autism, schizophrenia, bipolar disorders and leukaemia have been linked to the father’s advanced years.

A review of studies assessing the impact of advanced paternal age reported that children of older fathers have increased rates of psychiatric disease and behavioural impairments.

But while the increased risk of adverse health outcomes linked to older paternal age is real, the magnitude of the effect is modest. It’s important to remember that an increase in a very small risk is still a small risk and most children of older fathers are born healthy and develop well.

Improving your health can improve your fertility

In addition to the effects of older age, some chronic conditions that affect fertility and reproductive outcomes become more common as men get older. They include obesity and diabetes which affect sperm quality by lowering testosterone levels.

While we can’t change our age, some lifestyle factors that increase the risk of pregnancy complications and reduce fertility, can be tackled. They include:

Get the facts about the male biological clock

Research shows men want children as much as women do. And most men want at least two children.

Yet most men lack knowledge about the limitations of female and male fertility and overestimate the chance of getting pregnant, with and without assisted reproductive technologies.

We need better public education, starting at school, to improve awareness of the impact of male and female age on reproductive outcomes and help people have healthy babies.

For men wanting to improve their chance of conceiving, the government-funded sites Healthy Male and Your Fertility are a good place to start. These offer evidence-based and accessible information about reproductive health, and tips to improve your reproductive health and give your children the best start in life.

(Author:Karin Hammarberg, Senior Research Fellow, Global and Women’s Health, School of Public Health & Preventive Medicine, Monash University)

(Disclosure Statement:Karin Hammarberg works for the Victorian Assisted Reproductive Treatment Authority which manages the Your Fertility program)

This article is republished from The Conversation under a Creative Commons license. Read the original article.
 

(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)

Sperm donated in the UK is being exported to other countries and can be used to create large numbers of children across the world, violating a strict 10-family limit that applies in the UK, experts warned. According to The Guardian, while a single donor can be used to create no more than 10 families in UK fertility clinics, there are no restrictions on sperm or eggs from the country being sent abroad. This legal loophole is being exploited in what appears to be an industrial-level practice. It also raises the prospect of some donor-conceived children navigating relationships with dozens of biological half-siblings across Europe and beyond. 

Amidst this, experts are calling on the Human Fertilisation and Embryology Authority (HFEA) to tighten restrictions. “If you believe that it’s necessary to enforce the 10-family limit in the modern world then logically that should apply wherever the sperm are from,” said Prof Jackson Kirkman-Brown, chair of the Association for Reproductive and Clinical Scientists (ARCS), per The Guardian. “There is data showing that some of the children who find the really big families struggle with that,” he added. 

Separately, speaking to the outlet, Prof Lucy Frith, of the University of Manchester, who is researching donor-conceived experiences, said that making contact with biological half-siblings is often viewed positively. However, she added that “when numbers of siblings began to grow [it] felt unmanageable to have contact and relationships with a growing and indeterminate number of people.” 

“There are no hard and fast figures of when the number becomes ‘too much’ and this depends on individuals, but generally over 10 was felt to be a large group,” she said. 

“Once you’ve frozen sperm it doesn’t get any older,” said Mr Kirkman-Brown. This means that a donor sperm could continue to be used for years or decades. “You can end up with donor siblings older than your parents, which is not somewhere we’ve been yet,” he added.

Donations are “presented to donors as a beautiful gift to help someone create a family, not as, ‘We’re going to maximise the number of births from your gametes and make as much money as we can from that,'” said Prof Nicky Hudson, a medical sociologist at De Montford University. 

The rule for enforcing the 10-family limit across licensed clinics is controlled by HEFA. According to the regulatory body, 10 is the number people feel comfortable with in terms of the number of potential donor-conceived children, half-siblings and families that might be created. 

“As the HFEA has no remit over donation outside of HFEA licensed clinics, there would be no monitoring of how many times a donor is used in these circumstances,” said Rachel Cutting, director of compliance and information at the HFEA.

Also Read | Humans Experience Fastest Aging At These Two Ages, Reveals Study

Experts are now asking HEFA to crack down. “The HFEA is limited by its statutory duties, but it could stipulate that it will only import gametes that meet the UK limit (10 families), outside the UK,” said Lucy Frith. 

“The HFEA’s position that this is outside its remit is not good enough,” said Sarah Norcross, director of the fertility charity Progress Educational Trust. “I’m not against there being more than 10 families if some are outside the UK, but 75, which some of these banks have alighted on, is a heck of a lot of relatives. Even if they say we can’t control the number of families abroad, they could insist that the number is made available to the recipient,” she added. 

Notably, according to The Guardian, the United Kingdom was an importer of sperm till five years ago, mainly from the US and Denmark. But between 2019 and 2021, the UK exported 7,542 straws of sperm. Additionally, the world’s largest sperm and egg bank Cryos opened a unit in Manchester this April.

“The European Sperm Bank, which accounted for 90% of exports, applies a worldwide limit of 75 families a donor and estimates that its donors help on average 25 families,” the report said. 

“The idea of a dad to loads of children already exists in our cultural imagination. We don’t have that for women,” noted Prof Nicky Hudson, adding that it’s not an idea encouraged by women. One of them told her it “felt like human trafficking”. 

Representational image of a mother and child in Tokyo, Japan. The number of babies born in Japan last year fell for an eighth straight year to a new low in 2023
| Photo Credit: AP

The number of babies born in Japan last year fell for an eighth straight year to a new low, government data showed Tuesday, and a top official said it was critical for the country to reverse the trend in the coming half-dozen years.

The 758,631 babies born in Japan in 2023 were a 5.1% decline from the previous year, according to the Health and Welfare Ministry. It was the lowest number of births since Japan started compiling the statistics in 1899.

The number of marriages fell by 5.9% to 489,281 couples, falling below a half-million for the first time in 90 years — one of the key reasons for the declining births. Out-of-wedlock births are rare in Japan because of family values based on a paternalistic tradition.

Surveys show that many younger Japanese balk at marrying or having families, discouraged by bleak job prospects, the high cost of living that rises at a faster pace than salaries and corporate cultures that are not compatible with having both parents work. Crying babies and children playing outside are increasingly considered a nuisance, and many young parents say they often feel isolated.

Chief Cabinet Secretary Yoshimasa Hayashi told reporters Tuesday that the ongoing declining birth rate is at “critical state.”

“The period over the next six years or so until 2030s, when the younger population will start declining rapidly, will be the last chance we may be able to reverse the trend,” he said. “There is no time to waste.”

Japan’s biggest crisis: PM Kishida

Prime Minister Fumio Kishida has called the low births “the biggest crisis Japan faces,” and put forward a package of measures that have included more support and subsidies mostly for childbirth, children and their families.

But experts say they doubt whether the government’s efforts will be effective because so far they have largely focused on people who already are married or already are planning to have children, while not adequately addressing a growing population of young people who are reluctant to go that far.

The number of births has been falling since 50 years ago, when it peaked at about 2.1 million. The decline to an annual number below 760,000 has happened faster than earlier projections predicting that would happen by 2035.

Japan’s population of more than 125 million is projected to fall by about 30% to 87 million by 2070, with four out of every 10 people at age 65 or older. A shrinking and aging population has big implications for the economy and for national security as the country seeks to fortify its military to counter China’s increasingly assertive territorial ambitions.