Screen time can make a kid fat : Children who spend more time watching television, playing video games, using computers often spend less time exercising and such children tend to eat a lot snacks which deposit fat in their bodies. Since they do less movement and exercises, this fat accumulates in the body and the child will slowly become obeast. Obesity can result in diseases like heart failure, depression, diabetes and these diseases can be expensive to treat.
Weakens the relationship between kids and their parents: Since most parents have less time with their children because they have to work, kids have replaced their parents with technology. Dad or Mom will come back late from work and they will have less time to chat or play with the kid. So at the end of the day, the child will find comfort in playing video games, watching television, chatting with friends on facebook, visiting weird harmful websites online, etc. At the end of the day, these kids also consult the internet or online strangers for help if a need arises and this too can expose them to some wrong information which can result in problems.
Persuasive advertisements online expose them to risks: Kids who use the internet often are exposed to persuasive ads which might entice them to engage in some risky behaviors. Now days, we have so many video and humor sites created for adult entertainment, however, your kids can just Google the site and get exposed to this material. Risk behaviors like drug use, drinking, unprotected sex are promoted on such sites, so a kid will think that what they see is good for their lives since others are doing it.