Social factors Much research has focused on the impact on sexual development of the family environment in which a girl is growing up. Some studies examine the relationship between mother and daughter in affecting the timing of the daughter's sexual maturation. Others have looked at the impact of the father. Contamination A wealth of data from experiments with animals show that the rate of sexual development is vulnerable to various contaminants, contaminants to which people are widely exposed. Some epidemiological studies and case histories in the medical literature indicate sexual development in people also can be affected by contamination.
Data are also available linking human exposure to contaminants to earlier puberty.
Some of these studies come from epidemiological work with exposed populations. Others are from case histories in medicine.