Marriage penalty (in the US):

As I understand it, if both spouses earn approximately the same amount, with both earning "on the books," they pay more income tax filing jointly than they would if single. If the two incomes are significantly different, and/or if one's earnings are from the "underground economy," their net tax liability is lower when filing separately than it would be as two singles.

The underground economy includes not only such patently illegal sources of income as drug dealing, theft, etc., but also some perfectly innocuous occupations customarily persued on a cash basis -- waiting tables for tips, renovation carpentry (as opposed to new construction), musicianship (!) and many forms of self-employment.

Illegitimacy:

I am about to become a first-time grandfather; my daughter and her no-good boyfriend are not married. They are also not capable of supporting themselves, let alone a third human being, and my wife and I will undoubtedly wind up raising and supporting another young family just when we thought we had earned our retirement from such activity. The kids had expressed interest in getting married well before the pregnancy, but were discouraged by everyone (both families, most friends and acquaintances), and without our paying for everything, they could not possibly have married on their own. At the very least, they lacked the nerve and independence to elope -- they wanted to be *given* a wedding.

I realize that the usual scenario is for the young woman to get pregnant to force the issue of marriage, but in this case, knowing my useless common-law son-in-law, *he* is probably the one who poked holes in the condoms, or whatever, to attach himself to Maggie and to our family forever. Whether they marry or not, he'll always be our granddaughter's father.