Puberty
Stress. It is thought that people who are under a lot of stress start puberty later. Some research seems to show that girls have their first period a bit later when their fathers are not around when they are young when they have a stepfather if they have been sexually abused for a long time, or if they were adopted by their parents from another country at a young age. On the other hand, the first period may happen a bit later when a girl grows up in a large family with her natural father around. However, scientists are not sure how correct these studies are. Not many studies have been done to find out if stress also causes boys to start puberty later.