It sounds like he was giving her an opening to say what size fits. I would bet that his slender, fit daughter Vanessa, who is tall does not wear size 0, though I would bet that she is likely to ever have any extra weight as her father - and Kerry himself, slender though he is, likely would find a men's medium uncomfortable or too short in the arms.
This sounds more like actually caring if what he gave her would fit than awkward. Not to mention, what is the alternative? He could have given every woman small - including Candy Crowley! - but then there would be complaints from some on that too.
Frankly, the reported conversation was not all that different than chatter in my family when a sister was passing out T shirts at our reunion - and no one found that offensive.
From what I see looking at google image - she looks tall and broad shouldered!
http://www.google.com/imgres?imgurl=&imgrefurl=
http://pewforum.org/Christian/Evangelical-Protestant-Churches/The-Future-of-Evangelicals-A-Conversation-with-Pastor-Rick-Warren.aspx&h=200&w=300&sz=19&tbnid=3y61mQx5FIxzQM:&tbnh=88&tbnw=132&prev=/search%3Fq%3DJill%2Blawrence%2Bimage%26tbm%3Disch%26tbo%3Du&zoom=1&q=Jill+lawrence+image&docid=jxQERMT59We7zM&sa=X&ei=CTRdTtjzA9CSgQe93riKAg&ved=0CCAQ9QEwAg&dur=859