Scientists recruited a group of subjects from 82 women aged 18 to 35 years. They were asked to rate the body odors of the men and their faces. Each participant got six men: three of them were single, and three were in a relationship. The men wore a T-shirt for 24 hours, which the women then had to smell. The women also had to answer questions about how much they liked the smell and how sexy the man was.

The scientists found that the body odors of single men for all women were stronger than the odors of men in a partnership. Married participants also rated the faces of single men as more masculine. According to the researchers, women who are in a partnership during ovulation find the appearance of a single man more attractive than "busy" men.

“Women distinguish single men based on their testosterone levels. Higher testosterone levels are associated with stronger odor. A 2010 study found that single men have higher testosterone levels. From an evolutionary perspective, it may be advantageous for women to discover single men, as they will have more resources and time for women,” the scientists explained.