Convenience - or the future of the human race?  Where would we be without those handy plastics to wrap our foods in - but previous scientific studies on humans have found that phthalates, found in such materials,  are associated with poor semen quality in men and subtle changes in the reproductive organs in baby boys. 

These changes are brought about by interfering with testosterone levels.  In this new study, Doctors theorized that since low testosterone is also implicated in obesity and syndrome X, there might be a connection with phthalates there, also.

And indeed - there is!

Packaging chemical linked to male fat and insulin resistance