I can't find a single reference to "the common good" in my copy. You must have the version with all the emanations from the penumbrae inked into the margins.

Perhaps he meant “General Welfare.”

We the People of the United States, in Order to form a more perfect Union, establish Justice, insure domestic Tranquility, provide for the common defence, promote the general Welfare, and secure the Blessings of Liberty to ourselves and our Posterity, do ordain and establish this Constitution for the United States of America.

http://www.hi.com.au/eec/childless_case.htm

Childlessness as a Choice

Baum has conducted several studies and identified four major reasons why women choose to be childfree. These include:

Hedonists	women who want to maintain their standard of living lifestyle and who do not wish to sacrifice their time, energy or money in raising children
Emotional	women who have no emotional feelings for or affinity with babies or children (no ‘maternal instincts’)
Idealistic	women who do not want to bring children into a world they feel is unsuitable or unsafe, or who do not want to contribute to overpopulation or environmental problems
Practical	women who have a practical reason for remaining childfree, such as a wish to pursue their career, a preference to spend their time exclusively with a partner, or a fear of passing on a genetic disorder to children.