Hi. This may be a constitutional problem in your Case. I hope you have no problems with development of any other secondary sexual characters. Don't worry, you can try applying hair growth peptide lotions or minoxidil for about three to six months and see if it helps. Otherwise transplantation from scalp hair is the ultimate option. See a qualified dermatologist near you or send in further queries/ appointment request to follow up chat. Hope this helps. Warm regards Dr Govind Suresh Mittal. Excel care hospital. Bengaluru.