The study that says that single childless women are happier than married ones is not new. It possibly has to do with resources and responsibilities.

Married women with children have a lot of responsibilities, little free time and a lot of pressure. After all, taking care of a baby involves things such as not sleeping very much and being tired. Doing house chores is also tiring and cleaning the mess of two persons is more difficult than cleaning the mess of just one person who is the same that cleans so it is making an effort to not create so much mess.

It is easy to spot single women going on incredible travels and holidays and indulging in hobbies. So it makes sense that on average those women are happier. They also live longer and are healthier.

Now, to be fair, the women who chose to have children usually don't regret their choice. And once they get to retire, they might be happier too.

It would probably be interesting too to break the stats by age range. After all, being young and healthy helps to be happier than people old and sick.

But I won't discard the information just like that. I would analyze it to see if there is real correlation or other variables there.