What is the function of cilia in the trachea?

Volunteer bias

Explanation:

In the given situation the chances of participation of males in the study of sexuality is likely to more than the females or may be male volunteer may be available more readily. As the females are more inexpressive or may feel shy when asked for their own opinion related to topic of sexuality.

But males may be more comfortable while discussing topic related to sexuality . Thus this will create volunteer bias in the subjects of study.