Is baldness always hereditary?

Causes of "baldness": Alopecia is commonly known as hair loss, hair thinning, & balding. While genetic causes (like male pattern balding) are common, other causes exist: hormones, infections, autoimmune causes, metabolic (e.g. Chemotherapy), nutrition (e.g. Vitamin deficiencies), trauma (e.g. Tight braids), neoplastic (some cancers), etc. A dermatologist can help determine the cause & discuss treatment options.

No but commonly is: Due to various of genetic expression, baldness is not always hereditary but it certainly is likely to be transmitted with varying degrees of expression.