Men are comfortable talking to each other about salary, sex lives and sports - but won't discuss the changes their body faces as they grow older.
A study of 1,000 men aged above 40 found mental health, their dating life, and incontinence are topics many actively avoid discussing.
However, 67 per cent are an open book when it comes to weight gain and 66 per cent would happily talk about sports.
More than half (57 per cent) would keenly natter away about politics and their retirement (56 per cent).
And while 70 per cent would discuss hair loss with their male mates, only nine per cent would feel very comfortable discussing problems with erectile dysfunction.
Former England rugby captain, Lewis Moody, spoke about his own experiences with incontinence.
He said: "The stress that I added to myself by not telling other people added to the issues I was dealing with."
Nancy Sadler, spokesperson for TENA, which commissioned the research, said: “There are only a certain number of subjects which men generally feel comfortable talking about.
“It’s not surprising to see sport and politics topped the list and bodily functions came at the very bottom.
“It’s clear male health concerns are taboo topics among the population, but it’s something everyone faces, and it needs to be talked about.”
The research also found just 17 per cent would discuss ageing issues such as bladder leakage - even though 93 per cent were aware it could be a problem for men.
But 21 per cent would not tell anyone if they experienced it in the future, with half of those claiming it wasn’t anyone’s business.
However, of those who would, 79 per cent would raise it with their GP and 52 per cent would turn to their partner.
It also emerged going bald (63 per cent) or grey (61 per cent) were the changes that most men associated with growing old.
Weight gain, memory and hearing loss were also acknowledged as part of ageing, along with more nose and ear hair and growing a beer belly, according to the research, conducted by OnePoll.
Nancy Sadler, from TENA, which commissioned the research ahead of Men's Mental Health Month in November, added: “We knew there would be an element of people feeling self-conscious about their health issues when undertaking this study.
"But to hear how many men wouldn’t feel comfortable speaking about incontinence really shocked us.
“We’re determined to help people who experience incontinence, which is why our End Bladder Shame Campaign [https://www.tena.co.uk/men/learn-about-incontinence/end-bladder-shame] is so important.
“We’re committed to sharing real-life, authentic stories on the subject, creating a safe space for open conversation and, hopefully, ending any embarrassment that surrounds it.”
