Below are links to two helpful responses to "How Yoga Can Wreck Your Body". The first is written by Timothy McCall, who, according to the NY Times article "called the headstand too dangerous for general yoga classes". His article is titled, "How Not To Wreck Your Body Doing Yoga, or How I Really Feel About Headstand". The second article provides a balanced look at the contents of the original article, and what the NY Times failed to mention.
"How Not To Wreck Your Body Doing Yoga, or How I Really Feel About Headstand"
"A Balanced Look at the New York Times' "How Yoga Can Wreck Your Body" - What We Can Learn From William J. Broad's Research and a Response from a Long-Time Yoga Teacher"http://www.happyhealthylonglife.com/happy_healthy_long_life/2012/01/yoga-nyt.html
Remember, yoga is as safe as YOU make it- listen to your body! Refrain from allowing your ego to force you into poses you aren't ready for, and instead listen and know your limits. If you are breathing and in tune with yourself, you are practicing yoga.
The Conscious Informant