By the age of seven, 53pc of British children will own a mobile phone, according to a report by research consultancy Childwise.
By the time UK youngsters are 11, the ownership ratio reaches 90pc. This creates more opportunity for advertisers.
For now, advertising targeted at children has been slower to migrate online than in the broader industry.
Whereas more than half of the world's $614bn (€557bn) of ad spending is now online, less than a third of the outlay for ads targeting children is digital, according to a 2019 study by PwC.
That is partly because of concern from advertisers about the nature of online content. Nestle does not want its chocolate bars advertised alongside inappropriate videos, for instance.
But regulators have also been proactive in ensuring the necessary protections are in place for youngsters. The EU's General Data Protection Regulation makes it illegal to process the personal data of children under the age of 13, as does the Children's Online Privacy Protection Act in the US. Similar rules are in the works in China and India.
Theoretically, that keeps the big advertisers from serving children with digital ads catered specifically to their individual sets of interests. While it is possible to strategically target online ads to a precise subset of 18 to 35-year-old males, say those with a household income of $100,000 to $150,000 who are interested in video games and soccer, the same is not true for children.
However, that only holds up if parents are ensuring their offspring access the web through the appropriate portals. Tech giants like Apple and Google have come a long way in giving parents the tools they need to monitor and control their children's internet access (even if savvy youngsters have found ways to circumvent them).
Under pressure from investors, Apple introduced the Screen Time for Parents function to the iPhone in 2018, which lets parents see which apps their children are using and sets daily time limits for both the phone and individual apps. Google has similar functions in Android.
The pace at which children are getting their own smartphones means that the digital growth in advertising spend targeted at teens, pre-teens and younger is outpacing that for other ads. It will grow 22pc over the next two years, PwC estimates, outstripping the 13pc growth that the World Advertising Research Centre forecasts for online ads as a whole. If parents want to prevent their offspring from being bombarded with ads, they have many of the tools to do it.
As ever with all things digital, it may be that older generations require more education than their progeny.