Survey reveals people are more likely to bet on sport when there are major sporting events on... go figure...A summer of sport has provided a massive boost for the online gambling sector. The World Cup, the Epsom Derby and Wimbledon coinciding in June meant the sector saw a 15 per cent increase in punters on the previous month. While this result will probably surprise nobody - naturally people bet more when there are high-profile events taking place at the same time - there are other findings which may raise a few eyebrows. One statistic shows that almost one-fifth of all visitors to online gambling sites are under the legal age of 18, according to NetValue. A spokesman for Coral's online arm, Eurobet.co.uk, said: "I'm not going to say nobody under 18 has ever placed a bet online but we don't see it as a particular problem here and we're happy that we do everything we can to stop it happening. All users have to have either a credit card or debit card to bet on the site and we cross check all dates of birth given with the card companies. They won't be able to place a bet until all checks have been made." Unlike high-street betting shops, placing a bet online is (obviously) done remotely, so a teenager with a desire to gamble could always do so with an adult's card. "Of course if somebody wants to find a way around the system then there is always a way," said the spokesman, "but it's a question of responsibility: who's responsible for who?" But under-18s being drawn to betting sites is perhaps unsurprising given that NetValue's findings show they account for 20 per cent of surfers exposed to banner ads for betting services which often promise big winnings on relatively small investments. It is common practice for bookies to advertise on the official sites of football clubs, and other sports sites, which tend to have a youthful user base. While many will just be glad to hear that somebody is still advertising online, others, who have championed campaigns against cigarette advertising, for example, may take issue with this. However, Eurobet's spokesman said: "I'm sure there are much worse things they could see on the internet." Other surprise findings include the revelation that more than a quarter of gamblers, thought to be a predominantly male hobby, are mothers. This suggests that with the increasing infiltration of PCs into family homes, it is now easier for a mother, with children running around the house, to log on and place a bet than it is to find time to get down the bookies on the high street. But internet bookies gained customers across the whole spectrum of society during the World Cup as a result of the timing of matches, many of which kicked off outside business hours. However, the high-street shops covered the losses resulting from these early kick offs with strong showings for their online divisions. Coral, Ladbrokes and William Hill all reported considerable growth, month-on-month, with Coral's Eurobet.co.uk site witnessing the highest growth of 171 per cent.