KNTV Sex, described by the channel as the 'alternative guide to sex education,' goes out at 11am on weekdays. Aimed at 14 to 19-year-olds, it covers issues such as masturbation, sexually-transmitted diseases, fetishes, bisexuality and homosexuality.
It was among the most controversial programmes on Channel 4 last month, attracting 100 complaints from viewers. One said: 'I cannot believe that C4 would put such a disturbing programme on the air at 11am. The programme is not teaching anything except that sex is something amazing that you should do - it's absolutely disgusting.'
John Beyer of TV pressure group Mediawatch UK said: 'I think there are questions of compliance and how this show works with the broadcasting codes and the protection of children. Ofcom needs to look at this.
'The trouble is that Channel 4 just do what they want to do.'
Norman Wells of Family and Youth Concern said: 'Once again Channel 4 is seeking to push back the boundaries of what constitutes acceptable material for daytime television. The last thing children and young people need is another TV series that trivialises and cheapens sex and divorces it from any moral context.'
The complaints come not long after a row over another pre-watershed sex education series on Channel 4.
The Sex Education Show, which was screened at 8pm, sparked more than 200 complaints and led to accusations that the broadcaster was 'peddling obscenity' before the 9pm watershed.
KNTV Sex combines animation and comedy clips taken from TV shows.
It is presented by the animated characters Kierky and Nietzsche, two teenagers from the fictional country of Slabovia, which is described as the 'last communist state in Europe'.
Topics covered on the show include Operation Penis and 'amazing sex facts'.
A Channel 4 spokesman said last night it 'takes a new approach to dealing with important issues around sex and relationships education for a teenage audience'.
He added: 'This series is based on information and advice from both sexual health charities and teachers. There is no explicit imagery and the content is suitable for the morning schedule.' [Mail]