Final answer:
The inheritance pattern described is X-linked recessive inheritance, which affects males more often than females because males possess only one X chromosome. Females can be carriers, often showing no symptoms, while males will display the trait if they inherit the affected X chromosome.
Step-by-step explanation:
Inheritance Pattern Common in Males
The inheritance pattern for a trait that more commonly affects males than females and can be seen in brothers or fathers of a woman with affected sons is typically X-linked recessive inheritance. This pattern is observed because males have one X and one Y chromosome, whereas females have two X chromosomes. In X-linked recessive conditions, males are more frequently affected because they have only one X chromosome. A single recessive allele on this chromosome will produce the trait since there is no corresponding allele on the Y chromosome to counteract it. Consequently, females tend to be carriers of the trait, as they have a second X chromosome that usually contains a normal copy of the gene, masking the effects of the recessive allele.
In cases where the mother is an unaffected carrier (heterozygous for the trait) and the father is normal, there is a 50 percent chance that a son will be affected as he may inherit the X chromosome carrying the trait from his mother and a Y chromosome from his father. Daughters in this scenario, however, will either be carriers like their mother if they inherit the affected X chromosome or completely unaffected if they inherit the normal X chromosome. If a disease or trait is X-linked dominant, an affected father will pass the trait to all of his daughters (as they will inherit his X chromosome), but none of his sons (who inherit his Y chromosome).