Genuflecting: right, left, both?

[jdooley]

I see many people either use their left knee or not genuflect at all when entering a pew in Church. I was always taught to genuflect with my right knee before entering a pew when the Eucharist is present. Is this still the proper way to genuflect? When is it proper to do a genuflection with both knees?

 

[Fr.Charles_Grondin]

Eucharistiae Sacramentum:

1. Genuflection in the presence of the blessed sacrament, whether reserved in the tabernacle or exposed for public adoration, is on one knee.

General Instruction of the Roman Missal:

1. A genuflection, made by bending the right knee to the ground, signifies adoration, and therefore it is reserved for the Most Blessed Sacrament, as well as for the Holy Cross from the solemn adoration during the liturgical celebration on Good Friday until the beginning of the Easter Vigil.

Individuals who only bow might do so because they are unable to genuflect so we should be careful to reserve judgment.
Genuflecting on two knees is not required at any time, though there is a pious custom of doing so when the Eucharist is exposed.
Individuals who genuflect with the left knee either do so out of simply not knowing any better or perhaps they have a physical issue with their right knee.