Which research approach compares adopted children's traits with their biological and adoptive parents to assess hereditary influence?

Which research approach compares adopted children's traits with their biological and adoptive parents to assess hereditary influence?

• A. Twin studies
• B. Family studies
• C. Case studies
• D. Adoption studies

Answer: (D)

Adoption studies isolate genetic influence by using a design where an adopted child shares genes with biological parents but grows up with adoptive parents. By comparing the child’s traits to both sets of parents, researchers can see whether similarities align with biology or with the rearing environment. If a trait tracks with biological parents, that points to heredity; if it tracks with adoptive parents, it points to environmental influence. This direct partitioning of genetic and environmental contributions is what makes adoption studies the best approach for assessing hereditary influence. Twin studies compare identical and fraternal twins to estimate heritability but rely on assumptions about shared environments; family studies look at relatives but can confound genetic and environmental factors; case studies are in-depth analyses of individuals and don’t generalize to heredity.

Adoption studies isolate genetic influence by using a design where an adopted child shares genes with biological parents but grows up with adoptive parents. By comparing the child’s traits to both sets of parents, researchers can see whether similarities align with biology or with the rearing environment. If a trait tracks with biological parents, that points to heredity; if it tracks with adoptive parents, it points to environmental influence. This direct partitioning of genetic and environmental contributions is what makes adoption studies the best approach for assessing hereditary influence. Twin studies compare identical and fraternal twins to estimate heritability but rely on assumptions about shared environments; family studies look at relatives but can confound genetic and environmental factors; case studies are in-depth analyses of individuals and don’t generalize to heredity.