Human physical appearance is the outward phenotype or look of human beings. There are infinite variations in human phenotypes, though society reduces the variability to distinct categories. The physical appearance of humans, in particular those attributes which regarded as important for physical attractiveness, are believed by anthropologists to affect the development of personality significantly and social relations. Humans are acutely sensitive to their physical appearance. Some differences in human appearance are genetic, others are the result of age, lifestyle or disease, and many are the result of personal adornment.