Scientific advances are confirming what parents have long known: the teenage brain is “a very complicated and dynamic area” (National Institute of Mental Health, 2001). When the United States Supreme Court considered the death penalty as applied to crimes committed by a person under the age of 18 in Roper v. Simmons (2005) it received summaries of recent neurological evidence showing that teenage brains are not fully developed. Newly available magnetic resonance imaging (MRI) research, several briefs argued, established that teenagers as a group lack the capacity of the typical adult to make decisions, avoid risks and understand the consequences of their actions and that they are therefore less culpable for violent acts than adults. In Roper the Supreme Court held that persons may not be subjected to capital punishment for crimes they committed between the ages of 16 and 18. Dissenting, Justice Scalia zeroed in on a key analytical problem. He challenged the majority to explain how it is possible to reconcile the view of teenagers as too young to be “treated as adults” when they commit capital offences because they “lack the ability to take moral responsibility for their actions” with the jurisprudence and scholarly literature justifying rights for minors, including the position that adolescent girls are “mature enough to decide whether to obtain an abortion without parental involvement” (Roper v. Simmons, 2005 (Scalia, J., dissenting, p617)).