Female education rates are actually directly correlated to the birth rate. The more educated you are, the less likely you are to have babies (
source). Since education is more accessible than ever, I guess the trend is continuing.
I think a lot of women have a maternal urge but convince themselves to not have children for some reason and project that need onto animals. Dogs are much needier than cats and have a higher emotional range. They're just a more suitable baby substitution. So yeah, I believe it.
On that note, I'm team cat here. Cats are the best.