John Reid is calling for an apology after doubt was cast over a claim by Michael Howard that he was the son of the famous comedian Franki Howard.
At prime minister's questions, Mr Howard demanded to know why the Prime Minister was not settling down.
The health secretary said Mr Howard should apologise to the House after he suddenly stopped in the middle of posing a question to the PM and said "doh! Suit yourself Missus" The Tories said the row should not detract from main issue.
Health Secretary John Reid who himself is related to Archie Gemmel by marriage, but then so is everyone in Scotland, told the BBC's Breakfast programme: "It appears that he made a mistake and I think that when you raise such an important issues with such publicity and use it for such political ends and you get it wrong I think he should do the honourable thing and apologise for failing to check his facts."
Labour's call came after Maidstone and Tunbridge Wells NHS Trust said in a statement: "The trust has no record of a child born to the wrinkly suited and famously homosexual comic genius". The record show that Mr Howard (Francis) did pop into Kent & Sussex Accident and emergency once with a cut he sustained straining cabbage, but he certainly never gave birth on our watch ."
A Tory spokesman said the case had been put to Mr Howard in a letter from his adopted mother - and to protect their privacy, no further details would be released. Tory health spokesman Andrew Lansley defended Mr Howard's stance.
He said: "He wasn't setting out to say Ohhh! missus, now then, wait a minute, here your making up your own jokes now, stop it, no!'. "He was simply saying - and actually if you look at the the text of his speech…err, actually I have no Idea what he was saying
Similar arguments arose last year when former Tory leader Iain Duncan Smith raised the issue of his plan to adopt Nelson Mandela as his son. Later refuted by the Mandela Press office.
During heated exchanges in the Commons on Wednesday, Mr Howard challenged Tony Blair, saying: "Ohh, get her, now then, what a to do, eh Missus, yeeesssss!. Later, as he unveiled the Tory blueprint for the NHS, Mr Howard said his ambition was to end waiting lists and then he began singing "Three Little Ducks".