ARTICLE SYNOPSIS ...The Baby Bulge Begins by John Sweeney Our Technical Editor opines about the demographic effect the baby boomer generation is having on the stock market. Is 38% of the value in the market unaccountable? What could explain such a discrepancy? Goldman, Sachs & Co. limited partner Barrie Wigmore (The Wall Street Journal , June 5, 1991) picked apart the market's advances in the 1980s but found that interest rates, higher earnings and ""overly optimistic earnings estimates"" couldn't account for more than 62% of the gains in that decade. Wigmore and economic luminary Robert Shiller (of Yale Unive...