Content Warning: This section of the guide discusses suicide, suicidal thoughts, and sexual assault.

Melissa went salsa dancing with a friend and met Rob, to whom she was instantly attracted. The attraction developed as they talked and danced, but they parted without exchanging numbers—instead, Melissa suggested Rob could find her online. Brizendine states that men are chasers while women are choosers, and mate selection is based on biological factors, including symmetry and pheromones. Some theorize that modern reproductive behavior is driven by primitive instinct: For example, David Buss found similarities in mate choices throughout 37 cultures. Brizendine claims that Melissa’s coyness resulted from her subconscious skepticism of Rob’s ability to provide financially. Female humans can only procreate approximately once a year, so they must be selective, which is why Melissa did not sleep with Rob or offer contact information. Brizendine claims that women prefer taller, older, financially secure men, while men prefer attractive, younger women. Traditionally feminine physical attributes are signs of fertility. Brizendine states that female hourglass body type indicates higher estrogen levels and the ability to become pregnant more easily. Male mates also want loyal female partners, so Brizendine speculates that had Melissa slept with Rob, he would not have wanted a long-term relationship with her.