20 years is not enough to study and fully understand the impact of this new technology. See, the effect of high-intensity laser treatment might not be visible on the first generation of those who directly underwent this kind of treatment. You know how laser beams can alter the molecular constitution of cells in our body and even cause genetic alterations that may be passed on to later generations and visible at a much later point in time. So the impact of laser beam hair removal treatment cannot be observable in a 20-year period but across several generations.