An experiment by psychologists from Macquarie University has shown that heterosexual women can smell which men are busy and which are not, Frontiers in Psychology reported.

The researchers recruited a group of subjects from 82 women between the ages of 18 to 35 years. They were asked to assess the body odors of men and their faces. Each participant received 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.

Researchers found that the body odors of single men were stronger for all women than those of men in partnerships. Married female participants also rated the faces of single men as more masculine. According to the researchers, partnered women at the time of ovulation found a single man's appearance more attractive than busy men.

Women differentiate 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 point of view, it may be advantageous for women to find single men because they will have more resources and time for women, the scientists explained.