Baby Arbitrage?

N. G Mankiw posted a link to the following article in NY Times.
The gist of the story is, with a huge tax benefit for having the baby before the end of the calendar year, people are starting to strategically bringing some January babies early into the world. Another example how the discontinuity in tax code create discontinuous behavior! The best part of the story is, wealthier people who are more likely to have tax-advises from experts, give birth to more "year-end" babies. Woh, let's wait and see more Ivy kids with a date of birth in December, 18 years later!