1930 U.S. Federal Census > Wisconsin > Rock > Plymouth > District 47 > Page 1B
David M Spencer, 62, Head, age at 1st marriage 21, b. Ohio, father b. Ohio, mother born Ohio; occupation section head, C.N.W. Rwy
Lelah/Lilah (hard to read) A Spencer, 39, Wife, age at 1st m. 21 (so this is her first, his second, unless the enumerator made a mistake), born Wisconsin, father b. New York, mother b. New York
Children, all born Wisconsin: Alva D Spencer, 15, Son, Melvin S Spencer, 12, Son Margaret E Spencer 10, Daughter Robert J Spencer, 5, Son Elanor D Spencer, 4, Daughter
So - she was born about 1891. My experience with census records tells me that date is accurate give or take 5 years. She and David married about 1912, again +/- 5. Alva comes along a year or two later, in 1915, which fits.
The Social Security Administration will sell you a copy of an SSN application for $27. It is better than a death certificate because the person himself /herself filled it out while he/she was still living. SSN applications have the person's name, birth date and birth place; mother's maiden name, father's name; place of employment, job title and home address at the time of application.
Click on "SS-5" on the SSDI site and the wizards at Roots Web will even format a letter to the SSA for you.
I'm not related. I find genealogical puzzles more interesting than cross-words.