Underwear
Wearing tight jeans, underwear, or pants can leave the vaginal and scrotal area without enough air to remain clean and dry or unable to properly breathe. This can cause UTI and other infections of the urinary tract.
Specific underwear material can exacerbate or ease the issue. Natural fabrics and cotton are best. Synthetic material, nylons, and spandex can be too stifling and may cause excess moisture and sweat. Excess moisture and sweat is what lead to growth of bacteria.