The presence of mold does more than merely offend aesthetic sensibilities. It can make you sick. It can cause allergies and create toxins.
If you're allergic to mold, you may find yourself sneezing or coughing. Your eyes and skin could become irritated.
Some people who are allergic to mold have a powerful reaction. The presence of mold can cause them to become feverish or short of breath.
Those whose immune systems are compromised, or who have chronic lung disease, can develop infection in their lungs just from the presence of mold.
Take steps to protect yourself. Keeping the moisture down helps to discourage the presence of mold because mold spores need a warm and humid environment to grow. Fix any leaks, use an air conditioner or dehumidifier. Provide good ventilation.
"The term 'mildew' is sometimes used to refer to some kinds of mold, particularly mold with a white or grayish color or mold growing in shower stalls and bathrooms. Mold may grow indoors or outdoors and thrives in damp, warm, and humid environments. Mold can be found in essentially any environment or season."
http://www.medicinenet.com/mold_exposure/article.htm