Laser hair removal will not affect your daughter's hormones, nor will it cause any other harmful systemic effects. This is an age group in which the patient's maturity level is the best predictor as to whether or not she/he would be a good candidate for laser hair removal. Some eleven year-olds are very mature and are able to understand why they are having the procedure as well as the fact that it may cause some discomfort while it is being performed. If your daughter is self-conscious about the amount of hair on her arms and legs and wants to have the procedure (and you, as her legal guardian consent to her having it done), I see no problem with treating someone of that age. Oftentimes, I see younger patients wanting treatment to remove excess eyebrow hair that causes a "unibrow". This is something that can be fixed relatively easily with several laser hair removal visits and can really boost that child/teenager's self-esteem. With the newer lasers on the market for hair removal, pain during treatment is substantially less and the procedure only takes a few minutes. An experienced and compassionate physician will take extra time with younger patients, ensuring that they are comfortable by using numbing cream prior to treatment and explaining each step of the procedure along the way. If I get the impression that the child/teenager is not necessarily bothered by the hair and is hesitant to have the procedure (that it's more of a cosmetic concern of his/her parent), then I will advise them to hold off on having it done. Even though the patient is a minor, its important that he/she is involved in the decision of whether or not to have the laser hair removal treatments. So, to answer your question, if your daughter is self-conscious about excess hair on her arms/legs and is mature enough to understand that the procedure is not completely painless (and you, as her parent, support her decision), I see no problem at all with treating her (or even someone younger than her).