Alternative theories as to why male and female pattern baldness occur: One plausible theory to explain some of the difference between men and women is based on the angle of follicles and resultant sebum build-up. The angle at which hairs come out of a female scalp allow the sebum (oil produced by the scalp) to "run off" whereas the angle of hairs on a male scalp (straight up) can lead to oil blockage.

Recently, a group of Japanese researchers reported a correlation between excessive sebum in the scalp and hair loss. Excessive sebum often accompanying thinning hair is attributed to an enlargement of the sebaceous gland. They believed excessive sebum causes a high level of 5-alpha reductase, the enzyme which converts testosterone into dihydrotestosterone (DHT), and pore clogging, thus malnutrition of the hair root and a shift into the resting phase.

Although this condition could be hereditary, they believe diet is a more likely cause. The researchers note that Japanese hair was thick and healthy, with a small gland and little scalp oil, until large amounts of animal fat crept into their diet after World War II. This change has led to a significant height increase in the Japanese population, but it has also resulted in more Japanese men losing hair. To some extent, their observation makes sense: problems with greasy hair have often been noted as much as six months to a year prior hair thinning becoming noticeable. However, this might just be one of the symptoms instead of an underlying cause, so more research is needed.