How is hair loss inherited by women?

Women are more likely to experience hair loss if they inherit "BB"

Androgenetic alopecia and genetics is a complex subject, especially when it comes to women. In men, hair loss is thought to be caused by a combination of both genetics and androgen, however it isn't known whether this condition is the same in women. The relationship between genetics and androgenetic alopecia is widely controversial in the medical community, since the exact genes causing androgenetic alopecia haven't been identified yet.

The gene that is most widely believed to be involved in androgenetic alopecia are the ones that take part in androgen production, converting androgen to dihydrotestosterone (DHT) and the activity of androgen receptors.

Dorothy Osborn theorized that hair loss in both men and in women is largely due to one gene with two alleles, b (non-balding) and B (balding). Dorothy proposed that balding happens in homozygous (BB,meaning they have the same alleles at a certain gene locus on homologous chromosomes) and heterozygous (Bb, meaning they carry a different version of that gene on each of on the two corresponding chromosomes) men; but only in homozygous women. She concluded that just one autosomal gene, named “B,” accounted for the genetic predisposition to hair loss, and acted in an autosomal recessive manner in women and an autosomal dominant fashion in men. In layman's terms, this means men are more likely to experience baldness if they inherit either “Bb” or “BB”; where as women are only more likely to inherit hair loss if they inherit “BB.”