Fathers4Justice has been criticised by the advertising watchdog for a national campaign attacking the parenting website Mumsnet.
The pressure group ran a press advert on March 16 headlined: "Say it with hate this Mother's Day". The ad showed a picture of a toddler with various negative words written all over his body including pig, rioter and wife beater.
The text stated: "Fathers4Justice are writing to all advertisers this Mother's Day to inform them that the Mumsnet web site carries abusive and distressing anti-male content which promotes gender hatred against men and boys.
"We believe that the general sexist labelling of men and boys as 'rapists', 'paedophiles' and 'wife beaters' is as unacceptable and offensive as racism and homophobia."
The pressure group asked advertisers to suspend their advertising on Mumsnet "until founder Justine Roberts adopts a zero-tolerance policy to gender hatred".
Ten people complained on three issues:
:: Whether the claim Mumsnet carried anti-male content was misleading and could be substantiated.
:: Whether the claim that Mumsnet had unfairly generalised men and boys as rapists, paedophiles and wife beaters was misleading and could be substantiated.
:: Whether the picture of the toddler with various derogatory remarks written over his body was offensive.
The first two were upheld by the Advertising Standards Authority which ruled the advertisement must not appear in that form again.