Moisture is really the key cause of mold growth. Essentially, the difference between whether mold grows in your home or not comes down to whether you have a moisture problem.
If you live where humidity in the air is naturally high then mold growth in your home can also be a recurring problem. Mold can start growing from different leaks in the home such as leaks in pipes and in the roof. Poor ventilation can also cause mold. It is important to reach out to a professional when dealing with mold. There are certain companies that are dedicated just to mold remediation.