Girls who show significant signs of puberty and its progression through growth spurts and bone maturation before age 7, and boys before age 9, are considered precocious. It's usually for reasons we don't understand. About 1 out of 5,000 children are affected.
"Thumb-sucking is a proper and helpful conduct for exceptionally small kids," Thumb-sucking also can lead to dental problems. A child who is still thumb-sucking by age 5, when permanent teeth start coming in, may develop an abnormal bite. Beyond a simple overbite, some children develop speech problems: troubles with the "S" sound and other "tongue-tip" sounds,