Actually JTT, there are a number of excellent US historians who have done a fine job of documenting female emigration from Ireland to America: one is Hasia Diner, the other is Janet Nolan. Their observations are even in concurrence with the male historians!

You seem to have a problem with the interpretation of the historic facts, JTT, because it makes the Irish look sexist. They were. Very. Their treatment of their female citizens at the time was appalling--they were largely viewed as chattel.

My "unscientific observations" aren't any such thing. They are now, in the canon of US immigration history, well established facts.

The reason why both girls and boys emigrated to America was largely the same: the punitive and regressive dowry system that developed in post-Famine Ireland.