John, the Erica Schwartz op-ed in the Journal is a nice read. It’s a subscriber only one though (and dead-tree newstand):

[People] want to figure out the system, break the code of their child’s sex through Internet checklists, Chinese lunar calendars, “pee tests” and stargazing. It might make nine months of waiting more fun, but ultimately the odds are 50-50. It’s not what one would call a remarkable feat to guess right. If there were 10 possible sexes to choose from, people might find themselves a little less inclined to count calories, pounds or zits and more inclined to book time with a sonographer.