While they did use their idea about moving hair from the sides and back of the head to the balding areas, they did not have pleasing results. These hair transplant procedures in the 1960s and 1970s used a method where 15-25 hairs were grafted in a round plug pattern. These plugs were both conspicuous and unsightly. Based on the fact that the average Caucasian male has a density of 2 hairs per millimeter, it can be assumed that the average density of hair is 1250 hairs per square inch. Figuring at an average of 2 hairs per follicular unit, it would take 625 follicular units per square inch. To get 25% of that, you would need 156 follicular units per square inch. Hair transplant procedures that use cloned hair are farther off, though. The research cannot be done as to whether these hairs can safely and effectively be transplanted onto a person's scalp yet. First, they cloning process will have to be completely perfected. Only then can the hair transplant trials begin. Your doctor will need to prepare you for the surgery so that you will know exactly what to do to make the procedure go better. If you follow instructions, you will have a much better outcome. When the doctor sees you a couple of weeks before surgery day, she will go over again exactly what procedure you are getting. The hair has to come from somewhere on your body. Wherever you take the hair from is called the donor site. There can be different donor sites for different people. The most common donor site for hair transplant surgery is on the head. If the sides and back of your head have full lustrous hair, you are in luck. Some people have hair transplant surgery to their eyebrows because the hair has simply fallen out over time. Others have thyroid disease or other diseases that affect their hair. A certain type of alopecia results in eyebrow loss. Excessive plucking can be a problem, too. Burns, tattoos, and infections can cause the eyebrow hair to fall out, and some people just are not able to grow eyebrows at all.