We study private demand and preferred governance for human enhancement technologies using a nationally representative survey experiment of U.S. adults (N=5,614). Respondents evaluate randomized vignettes varying benefit domain (cosmetic, health, productivity), mechanism (genetic vs. non-genetic biotechnology implant) and heritability, purpose (restorative vs. enhancing), and side-effect severity. Stated adoption is highest in health scenarios and lower in productivity and cosmetic ones; it falls sharply with severe side effects and enhancement framing, with an enhancement penalty comparable to the risk penalty. A sizable minority are never-adopters even when large benefits are offered, consistent with resistance that is not fully explained by standard consequentialist tradeoffs.