While both can be very dangerous an understanding of these and any real hazard posed (as opposed to a presence) is critical.
Asbestos was used in home construction mostly from around the 1940s up until about 1970. It was often present in attic insulation, vinyl tiles, linoleum, siding/roof shingles, paints, and window glaze/caulking. Unless your home is older, asbestos is likely never going to be an issue.
As for mold.... it is all about moisture and moisture control control.

Asbestos: In the words of the EPA "If you think there may be asbestos in your home, don’t panic." Follow this link to more information on asbestos in the home.
Mold: In the words of the EPA "Molds are usually not a problem indoors, unless mold spores land on a wet or damp spot and begin growing. Molds have the potential to cause health problems."
If you are in the market for a new home and either of these show up during an inspection it is critical to have the situation evaluated by a qualified licensed professional.