That's been a requirement since 2002. It was a change to bring us to international standards. Children used to be allowed to be added to a parent's passport. It wasn't something we encouraged. It was cumbersome. The child could only travel with that parent, but couldn't be on both parents' passports.
We made the change in 2002 with a number of policy changes. It is a major initiative to help reduce child smuggling and to protect the integrity of children and their identities and their safety. We found it to be very effective.
It was a surprise when it first happened, but it's been really very effective.