In pedigree analysis with a rare autosomal recessive trait, what is the chance that two carrier parents will have an unaffected child who is also a carrier?
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Correct answer: 50%
For a cross of two carriers (Aa × Aa), offspring are 1 AA : 2 Aa : 1 aa, so any given child has a 50% chance of being an unaffected carrier (Aa).
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