Read the whole paper. They suggest theat it might be because of the health problems that they are nullparous. So it doesnt follow that intentional nullparity of

Read the whole paper. They suggest theat it might be because of the health problems that they are nullparous. So it doesnt follow that intentional nullparity of healthy woman results in shorter life. If their main claim is true that reproduction is taxing to the body than such nillparuty extends life