The oft-misunderstood hyphen is often left out of a phrase because of confusion about (or ignorance of) its purpose; occasionally, perplexity about the hyphen’s function is the cause of extraneous use, as shown in the examples below.
1. The mother-of-two said she had never seen anything like it before.
The simple descriptive phrase that provides more detail about the person requires no hyphenation: “The mother of two said she had never seen anything like it before.” Specifically, mother is hyphenated in a phrase only in rare instances of noun phrases such as mother-in-law and mother-of-pearl.
2. The rail authority originally planned to build from Burbank-to-Los Angeles before connecting the Central Valley to San Francisco.
Phrases describing starting points and destinations are not generally hyphenated: “The rail authority originally planned to build from Burbank to Los Angeles before connecting the Central Valley to San Francisco.” (An exception is when the phrase is a phrasal adjective modifying a noun: “The rail authority originally planned a Burbank–to–Los Angeles line before connecting the Central Valley to San Francisco”; here, en dashes are used instead of hyphens because at least one of the terms in the range consists of more than one word.)
3. Tasting menus range from $215 for five-courses and $255 for seven-courses at lunch to $325 for nine-courses at dinner.
Phrases in which a number serves as an adjective modifying a noun are not hyphenated: Tasting menus range from $215 for five courses and $255 for seven courses at lunch to $325 for nine courses at dinner. (Again, hyphens are appropriate in phrasal adjectives; here, an adjective and a noun combine to hyphenate a noun: “Tasting menus range from $215 for a five-course lunch and $255 for a seven-course lunch to $325 for a nine-course dinner.”)
You are quite right, Mr. Nichol:
“Specifically, mother is hyphenated in a phrase only in rare instances of noun phrases such as mother-in-law and mother-of-pearl.”
The common way of usage come in phrases like these:
1. The mother of all battles.
2. The mother of all hurricanes. (Example: Katrina in the Gulf of Mexico.)
3. The mother of all headaches (or “stomachaches”).
4. The mother of all mathematics problems.
(Such as proving the Riemann Hypothesis.)
5. The grandfather of all that is good and true in this country.
6. The father of the University of Virginia.
7. The mother of the American flag. (Betsy Ross, by legend)