It seems like recently there has been more and more emphasis put on the yoga asanas (poses), and asanas only. What is even more disheartening is that the yoga asanas have been generalized to the public as the all-encompassing word of 'yoga'.
Doing this leaves us to rely on one limb that is unstable when standing alone.
When people begin to think of 'yoga' as only a series of poses and the physical aspects of the practice are put on such a lone pedestal, we demote the holistic practice of yoga to a few stretches for our muscles. And we end up with a one-limbed animal which isn't a very effective vehicle for moving forward.
When we focus only on the physical aspects it's easy to view the benefits (or risks) from a narrow perspective, attaching any of those effects of the physical practice as the full effects of yoga. This view is more detrimental to the practice, to our spirit, and body, than any pose could be.
In the Ashtanga practice in the lineage of Sri K. Pattabhi Jois, yoga is an eight-limbed practice. Not only is the physical poses (asanas) only 1/8 of the practice, it's not even the first (or second) limb. No, the first limb is that of "Yama" which are the moral codes such as non-stealing and non-harming. The second limb is "Niyama" -- self observations such as contentment and cleanliness. The popular Western view of the practice tends to focus on the third limb of the "Asana" and sometimes also that of the fourth which is "Pranayama" or breath control. Beyond these there are "Pratyahara" (control of the senses), "Dharana" (concentration and cultivating inner perceptual awareness), "Dhyana" (meditation), and "Samadhi" (union, peace).
These other limbs essential parts of yoga that are not detrimental to ones body or spirit. My conclusion is to learn about yoga -- the full, holistic practice of yoga. Find a good and knowledgeable teacher who can assist you properly through the asanas and physical limb of yoga, but don't forget about the rest...
...for then you would be missing out instead of moving forward.