Between 2016 and 2018, many countries made their child pornography laws more similar, which let police from different countries work together more easily. In particular, the word "child" in the new child pornography laws is used as a synonym for legal minors under the age of 18. This can be confusing because "child" usually means a person who has not yet reached puberty. However, in 2007, the United States already had laws forbidding pornography with models under 18, and most people who were arrested for owning child pornography around that time had images of children who have not started puberty. 