The show was first announced in 2018 and was to follow the couple’s journey of starting a family via a surrogate, but it has been taken off the roster.
A BBC spokeswoman said that due to Daley’s "sporting commitments in the run-up to the 2020 Olympics, he was unable to film.”
She added: "Given the topicality of the subject and its exploration of the arguments for and against a change in the law, he agreed with the BBC it would have been impossible to complete the film in a satisfactory way that would have accurately reflected the situation at the time.”
However, a TV insider told The Mirror it was an odd move.
“There’s been some scratching of heads among observers as it was strange to unveil plans only for them to be shelved," said the insider.
“Tom would have had some idea what is involved in making a documentary and training. After all, he has competed at the Games in 2008, 2012 and 2016..."
Daley, 28, had been training for the 2020 Tokyo Olympics, where he went on to win gold. In 2018, the couple celebrated the birth of their son, Robbie, who was born via surrogacy.
The diving champ has gone on to make other documentaries for the BBC, including Tom Daley: Illegal To Be Me and Tom Daley’s Hell Of A Homecoming which both aired in 2022.
In Tom’s unreleased documentary, he was set to tackle the issue of the law that surrounded surrogacy in the UK at the time of creation.
In the UK, surrogacy is legal, but surrogacy agreements aren’t enforceable in law.
A surrogate also cannot be paid in the UK, save for "reasonable expenses", according to gov.uk.
However, in California, commercial surrogacy is legal.
The documentary would have explored those issues and also see Daley visit at least one other country where surrogacy is completely outlawed.