There is an interesting item at https://www.independent.co.uk/news/uk/home-news/women-happy-children-spouse-partner-relationship-unmarried-a8931816.html
The general drift is that marriage is broadly good for men but not for women and that having children brings a lot of stress that can have unfortunate consequences. This is not the first time that researchers have come to this conclusion.
The article ends with the important remark that this is a subject hidden under a strong social taboo which makes honest discussion virtually impossible. People say very different things when their spouse is in the room and when he/she is not.
The happiest group turns out to be childless spinsters. If you are female and want to live long and be happy don't marry and don't have children is the basic message. This, of course, flies in the face of what everyone is supposed to say and believe. When somebody gets married or has a baby we all say congratulations, but according to the research they have probably shortened their life and set the scene for a lot of misery that they might otherwise have avoided.