The early onset of puberty in children can be influenced by several factors:

1. **Genetics**: Family history plays a significant role. If a child’s parents or siblings experienced early puberty, the child may also be more likely to enter puberty at a younger age.

2. **Obesity**: Higher body fat levels can lead to earlier puberty in both girls and boys. Fat cells can produce estrogen, which can trigger the onset of puberty.

3. **Environmental Factors**: Exposure to endocrine-disrupting chemicals (EDCs) such as phthalates, BPA (bisphenol A), and certain pesticides can interfere with hormone levels and contribute to earlier puberty.

4. **Nutrition**: Adequate nutrition is crucial for normal growth and development. Malnutrition or over-nutrition (obesity) can affect hormone production and timing of puberty.

5. **Stress**: Chronic stress can affect hormone levels and potentially influence the timing of puberty onset.

6. **Ethnicity**: There are variations in the age of puberty onset among different ethnic groups. For example, African American and Hispanic girls tend to start puberty earlier than girls of European descent.

7. **Adoption**: Children who have been adopted may experience earlier puberty compared to the general population, possibly due to early life stressors or genetic factors inherited from biological parents.

8. **Improved Health**: Advances in healthcare and nutrition over the past century have contributed to a trend of decreasing age of puberty onset in many populations.

It’s important to note that early puberty can have implications for physical and emotional development, and consulting with a healthcare provider is advisable if there are concerns about a child’s development.