I interviewed a few researchers for this piece about whether men want children (and how no one seems to care) and learned that men simply weren't considered, period, when studies were being done about people wanting/not wanting children. I think it's changing, but slowly. https://kristentsetsi.medium.com/do-fewer-men-want-children-now-than-they-did-bef-just-kidding-no-one-cares-d283ee83a303