I'm going to be a research pedant here, but this article doesn't describe evidence for anything, except that, according to a YouGov survey, people who have a problem with gambling are more likely to buy scratch cards for their kids than those who don't.
This interpretation is is a leap:
Alexa Roseblade, a senior programme manager at GamCare, said ...
“We regularly hear how exposure at a young age can lead to other forms of gambling in their lives. This is particularly the case if young people experience a big win from an early age, where they might want to chase the feeling of that win again through other forms,” she said.
This may well be part of the stories they hear from those who have a problem with gambling, and it may be that those individuals are right to attribute their difficulties to early exposure.
But in order to determine causality you'd have to look at other factors influencing problem gambling and, crucially, how often people who are bought scratchcards as kids DON'T go on to develop problems with gambling, vs how often they do.
In theory, you'd have to do an RCT and thus give scratchcards to a randomly selected group of kids, but I guess that's not getting g ethical approval!
In any case, the sort of stories described here seem like more than buying a scratchcard for a birthday.