Puberty
Diet. Boys and girls who have a good diet – who eat healthy food – tend to start puberty earlier. Today, people start puberty younger than in the 1840s. For example, in Norway, girls born in 1840 had their first period (see below) at an average age of 17 years; in France the average age was 15.3 years; and in England it was 16.5 years. This may be because people have better food to eat today.