What is a key characteristic of dominant traits?

A key characteristic of dominant traits is that they are always expressed in the phenotype when at least one dominant allele is present. This means that if an individual has one or two copies of the dominant allele, the corresponding trait will be visible in their physical appearance. This is a fundamental concept in genetics, highlighting how dominant and recessive alleles interact.

In contrast, recessive traits require two copies of the recessive allele to be expressed and can be masked by the presence of a dominant allele. Dominant traits are not limited to one gender or the other, making them equally expressed in both males and females. Thus, the assertion that they are only expressed in males is inaccurate. This distinction is crucial for understanding how traits are inherited and expressed in organisms.