Drive down any main road in Johannesburg and within minutes you will see a billboard advertising a sex-related website. Sex Trader, on which escorts advertise their services, has put up three massive billboards on the M1, just before the Sandton offramp.Even taxis, which children might use, advertise nightclubs that feature strippers.The sex adverts are likely to stay if recent Advertising Standards Authority rulings are anything to go by.The watchdog has dismissed complaints by aggrieved parents about street adverts promoting adult content.Heather Kirkland complained about adverts for adult website Red Velvet, showing a woman in a provocative pose, saying they were not suitable for street poles as they informed under-age children where they could gain access to adult content on a website.Red Velvet's holding company said the ads were not "widely offensive"."The adverts have been used extensively, with anywhere between 60 and 80 billboards displayed, for over two-and-a-half years, in just about every suburb in Johannesburg, Pretoria and Durban. They have literally been exposed to millions of people and there has been no public outcry regarding this advertising," it said.The Advertising Standards Authority said it could not rule against adverts just because they promoted an adult website. It had to decide if children were likely to be harmed by seeing the disputed advertising.Last month, the authority ruled that the woman in the bikini on the Red Velvet ad was no more risqué than images found on magazine covers."In fact, had this image appeared alongside a lingerie range, or perhaps a cosmetic product, consumers would likely not bat an eye[lid]."Child rights activist Joan van Niekerk said parents could use the signs to discuss sexuality with children, something that was often avoided."Sex is part of everyday life and we can't pretend it's not there. It is time parents took back their families and took responsibility for their children's sexual education," she saidSex therapist Dr Eve said the signs provided "teachable moments"."These billboards are showing a different facet of sexuality ... You have an incredible opportunity to begin talking with your kids and you can say: 'That is so unappealing That is not what I value. What I do like is love and marriage'."..