1. Heredity and Environment
Part I
Chapter Three
Heredity and Environment

2. The Genetic Code
What Genes Are
Variations

3. The Beginnings of Life Matching Genes Male or Female?
THINKING CRITICALLY: Too Many Boys?
New Cells, New Functions

4. The Beginnings of Life Twins Assisted Reproduction
THINKING CRITICALLY: Two Babies for the Price of One?

5. From One Cell to Many Epigenetics Gene—Gene Interactions
More Complications

6. Genotype and Phenotype
Current Consensus
Alcoholism
Nearsightedness
Practical Applications

7. Chromosomal and Genetic Problems
Not Exactly 46
Gene Disorders
Genetic Counseling and Testing
A VIEW FROM SCIENCE: Genetic Testing for Psychological Disorders