The Men's Health charity is defending a billboard campaign showing a close-up image of vocal chords that look like a vagina.
Men's Health chairman Phil Clemas said the aim of the campaign was to encourage men to talk about their health with loved ones.
"It was obviously quite confronting but the fact that it is a genuine image if your vocal chords, it is what it is.
"And it's a very direct connection between your vocals chords and talking and Men's Health felt that was appropriate to use that as a vehicle to get some talkability in the market."
Mr Clemas said he was confident the campaign meets the standards of the Advertising Code.
The Advertising Standards Authority said there had been no complaints about the billboards.