Can I include a note on extra-curricular activities in my SOP? I am a Molecular biology graduate, aspiring to do my doctoral study in U.S. Currently I am applying for several graduate programs. So far, my statement of purpose (SOP) mentions about my academic and research activities conducted till date. Should I mention about extra-curricular activities like playing badminton, active volunteer (weekend art classes) in an orphanage, etc.? Or I should be just professional by not adding the above stated activities.

I am confused of varied responses when I surfed internet for SOP templates. To be precise, I want to know whether adding extra-curricular activities in Grad school applications will boost my admission or not?? 

Thanks.
Think about this from the other side of the application: why would these activities cause someone reading the application to believe you a strong candidate for admission to Ph.D study?

If you can make a (non-tortured) case that your teaching skills improved because you taught art, that's a point in your favor; consider including it in the SOP. Badminton doesn't strike me as terribly relevant to molecular biology research, however, so I'd leave it right out.

(The calculus may legitimately be somewhat different for a professional program. The one I teach in looks for community involvement and leadership development, among other things, because both of those augur well for people in the professions we train for.)