The screaming is a seasonal thing, they are calling for a mate. They don't scream at their offspring, in fact they are remarkably quiet when they are not courting. In April the yougsters are just old enough to leave the den but not to support themselves. Aty first they don't go far, but play until their parents return. They bicker and squawk at each other, and they have a particular noise which greets parents returning to them with food after being away for a while. But very soon they learn (or pehaps it is built in) to be very quiet and melt into the background.
Only one in four of a litter survive to adulthood, so the numbers don't build up unless there is a lot of free food available - takeaway debris, handouts from well-meaning homeowners and so on. Cars account for a lot of casualties in September/October when the youngsters are leaving home to carve out their own territory in unfamiliar areas.
They start their own families in the New Year when they are 18 or 20 months old or so. Their first winter was spent just surviving and establishing a territory, and they may not survive it.