John F. Kennedy’s only grandchild Jack Schlossberg issued an unusual challenge to his cousin Robert F. Kennedy Jr.

Schlossberg, who has been openly critical of his relative, expressed his disapproval on Instagram on Wednesday, once again criticizing the Secretary of Health and Human Services.

‘RFK Jr…. I have got a challenge for you,’ he ranted from behind a desk, with an American flag sitting next to him.

‘Me and you, one-on-one, locked in a room, we hash this out. Nobody comes out until one of us has autism,’ he continued. ‘What do you say?’

The issue seems to involve making fun of Kennedy for his recent statements implying that either ‘toxins’ or ultrasound scans might be contributing to a significant increase in autism diagnoses throughout the United States.

During a press briefing last week, the nation’s top health authority even hinted at the idea that industries could be benefiting from environmental toxins that lead to autism – indirectly referencing his doubts about vaccines and his campaign against artificial food additives.

Kennedy had called the spontaneous press conference after a CDC report suggested the number of US children with autism rose to one in 31 in 2022, up from one in 36 in 2020 and one in 56 in 2016.

But scientists and advocates for people with autism have widely criticized Kennedy’s position as harmful and misleading, as mainstream research describes autism as a complex condition largely shaped by genetics.

Kennedy, though, dismissed the idea that autism rates are being fueled by genetic factors at his news conference.

‘We need to move away from the ideology that the relentless autism prevalence increase is simply an artifact of better recognition and better diagnostic criteria.

‘Doctors and therapists in the past weren’t stupid. They weren’t missing all these cases,’ he continued, arguing that ‘only a small percentage [of autism cases] can be charged to better recognition or better diagnostic criteria.

‘The answer is very clear and this is catastrophic for our country,’ Kennedy claimed.

He then said he would announce a series of studies in the next two to three weeks to identify ‘precisely what the environmental toxins are’ that may be contributing to the rise.

‘External factors, environmental exposures, that’s where we’re going to find the answer.’

RFK Jr promised ‘we will have some answers by September… there will be an answer for the American people very, very quickly.’

Yet Kennedy’s claim that the surge in autism cases is not due to better screening puts him at odds with the researchers behind the CDC report.

The authors stated that the uptick ‘might be due to differences in availability of services for early detection and evaluation and diagnostic practices.’

They also highlighted differences in insurance coverage.

Dr. Richard Frye, a leading autism expert from Arizona, also told DailyMail.com he was left with mixed feelings after hearing Kennedy speak last week.

He said that some of Kennedy’s claims – particularly the need to investigate common drugs including acetaminophen and antibiotics – were ‘spot on.’

But he blasted other factors floated by Kennedy – like ultrasounds – as ‘misguided’ and ‘theoretical,’ saying there’s no solid evidence they’re dangerous.

‘A lot of these things that RFK Jr is talking about are not things that have really conclusive science behind them,’ Dr. Frye, a pediatric neurologist at Rossignol Medical Center, told the Mail.

‘It is unfortunate that he concentrates on the wrong things, as it will slow down the emerging science and make things controversial,’ the doctor continued, adding that Kennedy’s rhetoric is hindering any productive conversation around prevention.’

But Schlossberg’s criticism of his cousin goes beyond the controversial autism statements.

He has repeatedly hit out at Kennedy ever since he launched his failed presidential run in 2023, when Schlossberg accused his cousin of ‘trading in on Camelot, celebrity, conspiracy theories and conflict for personal gain and fame.’

Schlossberg later teed off on his cousin during his Senate confirmation hearing, echoing his mom Caroline Kennedy’s brutal critique urging senators to reject his nomination.

Caroline called her cousin RFK Jr. a ‘predator’ who is willfully misinformed about vaccines, and a dangerous liar who has cheated his way through life.

Earlier this year, Schlossberg also took to Instagram and his 600,000 followers accusing Kennedy of ‘spewing lies’ that the CIA was involved in JFK’s assassination.  

‘Why are you scared of me? Why don’t you ever respond? Are you busy pouring [sic] over the JFK files? Or is Cheryl just really dry down there?’ he taunted his cousin, referring to his wife, actress Cheryl Hines. 

The following month, Schlossberg appeared to mock Kennedy’s spasmodic dysphonia – a neurological disorder that makes it difficult for him to speak, according to the Daily Beast.

He deleted his social media afterward, as he received flack for that and for falsely renowned lawyer Alan Dershowitz of killing his own wife.

Dershowitz has since said he’s not only threatening legal action, but also a full psychiatric evaluation of Schlossberg.

Schlossberg’s social media hiatus only lasted about a month, though, after which he posted an unhinged video in which he made kissy faces at Cheryl Hines and told her she should apologize for the recent death of an unvaccinated child with measles.   

‘Almost every single case of measles is in someone who’s not vaccinated,’ Schlossberg says in the video, in which he deliberately misspells the actress’s name as ‘Heins’ and at one point ‘Sheryl.’ 

‘I think you’re the perfect person to say sorry,’ he adds. 

But the Kennedy family is now refusing to ‘take blame or responsibility’ for the behavior of President John F. Kennedy’s quirky only grandson, Jack Schlossberg, declaring he’s more ‘Schlossberg than Kennedy,’ insiders have exclusively told DailyMail.com.

‘Members of the Kennedy family, although embarrassed by and for Jack, are adamant that they feel no blame or responsibility for his boorish online shenanigans,’ one such insider said.

‘They feel Jack’s dark persona is a clear case of “like father, like son”. That he’s a chip off the old block who inherited more the traits and characteristics of his father than having the Kennedy attributes of his mother.’