Hi. Greetings. This could be a genetic issue in case your father or brother too may have developed facial hair in their twenties. This could also be a constitutional issue where some people have fewer hair roots than others and would not develop very dense beards all their life. If other secondary sexual characters have not developed then it's worth seeing a endocrinologist. Else see a dermatologist near you and you could try minoxidil gel for whatever worth it may be. Hope this helps. Dr Govind S Mittal