Alice Jankell is tuned in to her kid's TV habits. She controls how much and what they watch.
"I'm afraid that if they watch too much TV, their minds will get lazy," she said.
A study of preschoolers found almost 70 percent watch television more than two hours a day. Researchers said those children are more likely to be overweight.
Overall, too much television means less time with friends. Studies suggest teens who watch more than two hours a day are more likely to have sex earlier.
In most families, both parents work and the television can be like a baby sitter, but experts said parents need to take television watching seriously and treat it like a health issue.
"As parents, you need to limit the number of hours. You need to be aware of what your children are watching. You need to be involved in your children's watching," said Dr. Christopher Lucas of the New York University School of Medicine.
Lucas said it is also important for parents to explain to children what is happening on the screen.
The American Academy of Pediatrics recommends children under the age of two should not watch TV at all, and older children should only be allowed an hour or two a day.