Abortion is the subject of fairly detailed, judge-made constitutional law in at least four different countries (probably more): the US, Canada, Germany, and (I think) France. These countries have very different constitutions and different institutions and traditions of judicial review. What explains the apparent convergence? Why has abortion apparently popped up as a divisive issue in so many different contexts, and why have these different courts all agreed to take on the problem of writing abortion law?
(The ultimate results of the decisions are arguably similar, too.)