Genetic Defect in Follicle Development?

I read the response regarding why hair transplants are permanent. I am balding and a biology teacher. (I use hair transplants as an example of grafting.) The question always arises, “Why is the hair different on the sides and back of the head than the top?” In light of your previous entry. What would cause a genetic defect in hair follicle development to affect only specific regions of the head? I would also like to know (because I constantly field questions about the uses of stem cells from my students) would the undifferentiated cells be able to be stimulated into new scalp skin (hair and all) for transplant? I have been presented with information about scientists experiment with growing a heart. Why not complete skin with sebaceous glands, sweat glands, arrector pili muscle, etc.? Thus would be a boon for burn patients as well as those of us who would like some hair back.

Thank you in advance

No one knows why we have developed male pattern baldness (MPB). You are right to ask if we can grow a heart from a stem cell, why not a hair? We actually have grown hairs from stem cells, but the ability to do this was completely inconsistent. Research will hopefully shed new light on this in the years to come.

You can review my previous post on a theory for this at Why Does the Back and Sides of the Head Not Lose Hair?