Yup, part of it is definitely that millennials have had it bashed in to them that it's super easy to get pregnant so never have sex without precautions and only stay thinking about having kids when you're "ready". Many millenials wait until they're thirty and probably think that they should be able to get pregnant in one or two months, when it can easily take half a year. At least that was my own personal experience trying to get pregnant. It became pretty stressful after trying a few cycles with no result.