First of all, worry is probably the wrong word - you don't get anywhere worrying about anything! Why should you care about your exposure to glyphosate, and more importantly, why should you limit your children's contact with it?
It is the main chemical in "RoundUp", the infamous pesticide being sprayed on much of what we eat, especially wheat. Genetic modification of wheat is done to make it "resistant" to RoundUp, meaning that they can spray loads of it without killing the plant.
Apparently, it has become common practice to spray huge amounts right before the harvest in order to dry up the plant which makes the harvest easier on the heavy equipment. The problem with that is of course leaving way too much on the final product, which we eat.
This chemical is known to disrupt our digestive system in serious ways. It also disturbs our hormones, possibly leading to weight gain or infertility. Finally, it is associated with an increase in childhood cancers. You don't want to eat this stuff, I'm pretty sure about that.
Here is a chart showing the parts per billion of glyphosate found from testing some common foods:
As you can see, most of these foods are thousands of times over the 0.1 ppb. level at which harm to health can be observed.
The solution? Buy organic when you can, and make food from whole ingredients, when you can. We probably can't avoid this stuff completely, but you can limit how much of it comes into your house!