What specifically makes you say this? It seems like one of those "common sense" conclusions that begs to be supported by data. The trend might surprise you. Abortion rates have fallen drastically since Roe v Wade (obviously Roe v Wade didn't itself reduce abortion rates, but improved education and access to birth control has been very effective). Has "hookup culture" also fallen drastically? How are abortions fueling hookup culture if they aren't happening as much?