Q. What is a “double genuflection,” and when should it be performed?
A. A single genuflection is the bending of the right knee to touch the place where the right foot stood, while head and back remain straight. It’s the customary act of adoration of Our Lord performed in the direction of the Blessed Sacrament in the Tabernacle.
A double genuflection, also an act of adoration, involves kneeling briefly on both knees, reverently bowing the head with the hands joined. Traditionally, it has served as a gesture of reverence reserved for the Blessed Sacrament when exposed to view (such as in a monstrance on the altar).
The Church’s general liturgical norms in most parts of the world no longer make any distinction between the mode of adoring Our Lord hidden in the Tabernacle or exposed to our view. The simple single genuflection on one knee is thus acceptable in both situations. But many Catholics find it deeply meaningful to continue the ancient custom of the double genuflection as an act of profound reverence toward our Eucharistic Lord.