When selecting breathable underwear, consider the following factors: - Material: Opt for underwear made from 100% cotton or other natural, breathable fibers. Avoid synthetic materials like polyester and nylon. - Fit: Ensure the underwear fits well. It should not be too tight or too loose. A snug but comfortable fit is ideal. - Design: Look for designs that provide good air circulation. Styles with a cotton gusset (the crotch area) are particularly effective.