How old should babies be before they sleep with security blankets? We have the Aden + Anais ones:
http://www.amazon.com/aden-anais-Muslin-Security-Blanket/dp/B004DCA22M/ref=sr_1_3?s=baby-products&ie=UTF8&qid=1371339254&sr=1-3&keywords=aden+%2B+anais+2+Pack+Muslin+security+blanket

I'm worried about SIDS and know there should be no bedding in the crib before age 1, but I hear of parents with littler ones using lovies and security blankets. DS is 5 months old, btw.