Step 1 : Introduction to the question "On which finger do human nails grow the fastest?"
...Infants' nails grow slowly but as any parent knows, as the child grows, the rate of nail growth increases. Nails usually grow the fastest during the early teen years, about age 10 to 14. After that, the growth slows and continues to slow as we age. Toenails tend to grow more slowly than fingernails and the rate of growth varies with each finger. Thumbs and pinkies tend to grow the slowest. The nails on the middle finger of the dominant hand tend to grow the fastest. Source: LiveStrong.com