Most people think that calculating the age of dogs and cats in "human years" is quite simple: multiply their age by seven. For example, a 4-year-old dog or cat would actually be 28 years old in human years.
But when you really begin weighing out the arithmetic, this method doesn't add up. Say a 1-year-old dog is the equivalent of a 7-year-old human -- get out of here! How many 7-year-old humans are sexually active and capable of reproducing? Dogs and cats are much more likely to have babies at 1 year old or even at 10 years old, than any person who is 7 or 70.
