Happy indeed is the scientist who not only has the pleasures which I have enumerated, but who also wins the recognition of fellow scientists and of the mankind which ultimately benefits from his endeavors.
At certain historic moments, grandparents took on childrearing responsibilities. In many cultures, they still do. Chinese grandparents who are able to retire at 55 are seen all over Beijing bouncing grandbabies. In the United States, we can't afford to retire at 55.