American teenage males have lower sperm count and testosterone levels than ever before. Now experts think they know why

Robert F Kennedy Jr issued a dire warning about the nation’s fertility situation.

The Secretary of Health and Human Services said in the Oval Office on Thursday:: ‘The average teenager in this country today has 50 percent of the sperm count and 50 percent of the testosterone of a 65-year-old man.’

The 71-year-old continued: ‘Our daughters are hitting puberty six years early and it’s bad, but at the same time our parents aren’t having children either.’

Now the Daily Mail has spoken to three experts who say Kennedy has brought significant attention to an issue they have been concerned about for decades.

But they added that his claims did not appear to be entirely true and that they were unaware of any data showing that young people’s testosterone levels were half as high as those of 65-year-old men.

It was unclear whether the secretary was comparing the sperm counts of today’s young people and old people or the sperm counts of today’s old people during puberty several decades ago.

But experts have warned that studies have shown sperm counts tend to fall across generations, which could be fueled by obesity rates and a sedentary lifestyle, as well as exposure to environmental pollutants such as plastic.

They said studies showed that the age of first period was also trending towards earlier ages, although they were not aware of evidence showing that for girls entering puberty earlier, this was happening six years earlier.

Reproductive endocrinologist at Boston IVF, Dr. Stephen Lazarou told the Daily Mail: ‘I think there’s a general perception that testosterone levels may actually be declining around the world. [male] generations.

‘There is some evidence, or some speculation, that environmental or lifestyle factors may contribute, and we believe this may be secondary to more sedentary lifestyles or increasing rates of obesity.’

urologist Dr. who runs a male fertility clinic in New York. David Shusterman added: ‘I have seen in my clinic that testosterone levels are declining, especially in younger men, and this may be what Kennedy is trying to point out.

‘In some cases, these guys look normal; ‘They are not overweight or have other factors that would put them at higher risk.’

RFK Jr. made the comments at a press conference hosted by President Donald Trump on Thursday, but he was also angry.In April, the same claims told Fox News that today’s teenager has less testosterone and sperm count ‘below 50 percent’ than a 68-year-old man.

A spokesman for the Department of Health and Human Services said: ‘Minister Kennedy is sounding the alarm about a public health issue that others are too timid or too politically cautious to confront.

‘A growing body of peer-reviewed research shows significant declines in sperm count over the last decade, and it is irresponsible to claim that this is not a serious trend.’

They pointed out two studies from 2017 and 2022; Both of these studies warned that sperm counts in men fell by 52 percent from 1973 to 2011.

Testosterone is the male sex hormone and is behind secondary male characteristics such as a deep voice and facial hair.

In men, it peaks in the early 20s and then gradually declines by about one to two percent per year; Researchers say this is a natural part of aging.

Experts told the Daily Mail that symptoms of low testosterone include low sexual desire, fatigue, decreased muscle mass, depression and weak bones.

It is also linked to sperm count; While normal levels indicate sperm production, low levels may cause the body to produce less sperm.

High testosterone levels as a result of supplements or testosterone injections can also reduce sperm count by interfering with other hormonal signals necessary for sperm production.

Inside A study conducted in 2017 published in the magazine Human Reproduction UpdateScientists examined sperm counts in 185 studies involving nearly 43,000 men between 1973 and 2011, HHS said.

They found that sperm count decreased by 52 percent during this period. North America, Europe, Australia and New Zealand.

In 2022, the same researcher, environmental medicine specialist Dr. Shanna Swan at Mount Sinai in New York, published a second follow-up analysisAlso cited by HHS, Dr. Swan says: Guard study suggested that the average sperm count could reach zero by 2045.

Some experts expressed concern about the paper, saying it compared semen samples using different methods for sperm count, which could make the results unreliable.

But another article January 2025 Similarly, after examining samples from 11,700 men between 1970 and 2018, they found a “modest decline” in sperm counts, but the researchers noted that this would not affect fertility.

Many experts have been sounding the alarm about declining male fertility for decades; The cause is unclear, but it has previously been linked to poor diet and exercise, as well as environmental toxins affecting the testicles.

Experts say a healthy man’s testosterone level is between 300 and 1,000 nanograms per deciliter (ng/dL), while a man with levels below that is considered to have low testosterone.

It’s unclear how many men have low testosterone, but symptoms of the condition include erectile dysfunction, loss of muscle mass, increased body fat, and mood changes such as irritability or depression.

Testosterone levels peak in young adulthood, around age 20, but decline by about 1 percent each year after age 30. These data come from a study at the University of Wisconsin.

Studies have also found evidence that young girls are entering puberty earlier than ever before, but not six years earlier as RFK Jr claimed.

An article published in JAMA May last year It found that women born between 1950 and 1969 started menstruating at an average age of 12.5 years, while those born between 2000 and 2005 had an average age of 11.9 years.

The researchers also found that the proportion of girls who started puberty before age 11 increased from 8.6 percent to 15.5 percent.

Although the proportion of people who started menstruating before the age of nine is still small, it has more than doubled over the same time period, from 0.6 percent to 1.4 percent.

Researchers said that in addition to childhood obesity, environmental factors such as nutrition, psychological stress and toxins that disrupt hormones may be behind this change.

But the change alarmed officials, who said it could be behind the higher risk of heart disease, cancer, miscarriage and even premature death.

However, Dr. D., a senior fellow in the Cato Institute’s Department of Health Policy Studies. Not all experts agree with RFK Jr, with Jeff Singer telling this website: ‘What I can say is that Secretary Kennedy took a few real studies and turned them into a sensational piece of sound.

There is some evidence of modest downward trends across generations, possibly due to lifestyle and health factors, but none of this comes close to Kennedy’s doomsday framework.

‘His claim grossly distorts the data and confuses normal aging with so-called generation collapse.’