Which type of genetic trait requires both parents to pass the gene for expression to occur?

The correct choice is the autosomal recessive trait. For a genetic trait to be expressed as autosomal recessive, both parents must carry a copy of the recessive gene and pass it on to the offspring. This means that the offspring must inherit two copies of the recessive gene—one from each parent—to express the trait. If only one copy of the recessive gene is inherited, the dominant gene (if present) will mask the expression of the recessive trait.

In contrast, a dominant gene only requires one parent to pass on the gene for the trait to be expressed in the offspring. Sex-linked traits depend on genes located on the sex chromosomes and can exhibit different patterns of inheritance based on gender. Polygenic traits involve multiple genes contributing to a single outcome, making their inheritance more complex and not reliant solely on two specific genes from both parents. Overall, understanding the specifics of autosomal recessive inheritance is crucial for predicting and identifying genetic disorders that require contributions from both parents.