When women are in those prime years (18-30), they are the best looking that they will ever be.... It's all down hill after that. All guys like to look at them.
All of the women "their age" are old and wrinkled and not too pleasing to look at. That's why old men stare at young women.... And wish that they can be that young again..... It's better than looking at the old hag their own age....
