The truth is that I don’t know, and neither does anyone else. Nobody has “debunked” the story either, which has been around for years. I don’t usually entertain stories like this one, but it is interesting.

Justin was born about 9 months after his parents took a trip to the Caribbean, and may have visited Cuba during that visit, although it hasn’t been confirmed. It is also true that Margaret Trudeau had a reputation for being fairly loose about sex. She purportedly had an affair with Ted Kennedy, for example.

Here is a pic of Justin with his “dad”, Pierre Trudeau. They look something alike.

I think he might look more like his mother.

Justin has blue eyes, as do both Margaret and Pierre Trudeau. Castro’s are dark.

Here is an excerpt from Medium.com:

View at Medium.com

First, Margaret Trudeau, Pierre Trudeau, and Fidel Castro were all notoriously sexually promiscuous. Margaret Trudeau was a partier who unquestionably had sex with men while married to Pierre. Nobody knows if Pierre objected. They met when he was 48 and she was 18. They got married when he was 53 and she was 23. Their marriage surprised Canada because Pierre had been a lifelong playboy with no wife or children. He would be turning 60 when she was barely out of her 20’s. She publicly states today she suffered from bipolar disorder and self-control issues. She smuggled drugs in the Prime Minister’s official government luggage. She sneaked away from official functions to get high. She partied scantily clad at Studio 54. She became embroiled in a scandal for having sex with Ted Kennedy (gross). According to Keith Richards of the Rolling Stones, Pierre broke up with her while she was having an affair with Ronnie Wood. The list goes on.

There is much more at the link.

Apparently Castro fathered 11 acknowledged children and it is said that he has multiple times that many bastards.

The Trudeaus apparently adored Castro. They, their aides and friends all said so. According to John English’s “Just Watch Me: The Life of Pierre Elliot Trudeau 1968–2000” they were charmed by Castro and made several trips to embargo-era Cuba just to see him. In 2000, Castro made a rare appearance out of Cuba to attend Pierre’s funeral in Canada.

I can see why this rumor has persisted. There is enough there for it to be possible. As the author sums it up:

The story is perfectly plausible. Pierre was an aging playboy who had fathered no known offspring despite being sexually promiscuous his whole adult life. Having recently become Prime Minister, it suited him to get married and demonstrate stability. He evidently wanted a family because that is exactly what he started. Sperm banks barely existed back then. If an infertile old man wanted to have a family, his wife had to do it the old-fashioned way. . .

If Ted Kennedy met her qualifications as a sexual partner, Castro was bigger, stronger, thinner, handsomer, and more powerful. From the photos is seems obvious she was attracted to him.