Most scissors are made for right handed people. However, those scissors aren’t designed for ambidextrous use. Because scissors have overlapping blades, they are not symmetric. The same can be said of the human hand, which does not close vertically, but instead has a lateral component to the motion.
When a right-handed person is using a pair of scissors designed for the right hand, the thumb pushes and the fingers pull inwards, pushing the blades together as you cut. However, if that same pair of scissors was used with your left hand, you would inevitably push the blades apart. While you may not notice any significant lateral movement, if you are cutting with the wrong pair of scissors you are more likely to just push the paper between the blades and possibly tear the paper.
Make sure if you have a left-handed child that you purchase a pair of left-handed kids scissors for them.