[Fancam] 110819 Taeyeon @ 2010-2012 Visit Korea Year {With thanks to 21CIMP}
Red Cross says you have to be at least 100 lbs at 22 years old. She was listed 44kg (about 100lbs) at debut and has probably lost a couple since then so I guess that makes sense.
http://imgur.com/14xCD..........................shorten