In what scenario might a woman be classified as at risk for developing breast cancer?

A woman may be classified as at risk for developing breast cancer in the scenario of being at least 30 years old and not having given birth. Age is a significant factor in breast cancer risk, as the likelihood of developing the disease increases with age. Additionally, women who have never given birth, or who had their first child after the age of 30, may also face a higher risk. This is thought to be connected to hormonal factors and the way the body undergoes changes throughout pregnancy and breastfeeding, which can provide certain protective effects against breast cancer.

The other scenarios do not logically correlate with an increased risk of breast cancer. Being underweight is not typically associated with an increased risk, and having no family history of the disease can actually lower risk rather than increase it. Similarly, having had no prior health issues does not inherently indicate an increased risk for breast cancer. Thus, the most accurate identifier of increased risk among the choices presented is the age and childbirth status described.