I think the selective focus adds interest to the composition as does the desaturation. The focus on the one eye draws my attention to the center of the image. Your artistic choice.
Thank you everyone for your most kind comments.
I would have loved the chance to shoot that image over again but it was one of those one of a kind moments. She just turned six a couple of months back and is still a cutie and her younger sister is perhaps even cuter.
Paul yes I still have that lens, maybe they'll let me take one of the two of them together for the challenge.
Steve, don't worry about sharpness here. Due to shooting wide open, the area of sharpness is small but is really tack sharp and the background is nicely soft. Some sources claim that the 1.8/50mm is sharper wide open than the 1.4 which has to be stopped down a bit for the same sharpness. As for the selection of the focal point, I second Paul's opinion; whether following that rule would have improved the image would perhaps be worth a try. A very nice baby portrait at any rate.
Gerald
On the contrary -- my sister who is a "real" photographer and has done lots of baby pictures, swears by the extremely shallow DOF on the face. I like it a lot.