How can genetic information about humans be inferred without direct experimentation?

• A. observing eggs under a microscope
• B. listing the genetic characteristics of individual humans
• C. making family trees that include information about certain diseases that related individuals have had
• D. fertilizing human eggs in a glass dish

Answer: (C)

Inferring human genetic information without experimentation comes from watching how traits pass through families. By building a pedigree that records who has a disease or trait across generations, you can see patterns of inheritance. If a trait shows up in every generation and affects both sexes, it often points to a dominant autosomal allele. If it skips generations or mostly affects one sex, it suggests recessive or sex-linked inheritance. From these patterns you can deduce who might be carriers and estimate the risk that future children will inherit the trait, all without performing any lab experiments on people.

Observing eggs under a microscope doesn’t reveal how traits are inherited in humans. Listing genetic characteristics of individuals gives direct data rather than inference. Fertilizing human eggs in a dish is an experimental procedure, not a way to learn inheritance patterns from family data.