Thanks for asking the question; I hadn't noticed that we guys were weaker at remembering faces. (Typical man, right?)
Apparently, it's so. I found a Time online article on this, which said:
"In lab settings, women routinely outperform men in facial-recognition skills, both in terms of speed and reliability. Imaging scans have shown that part of the reason is that men rely only on the right side of the brain in summoning up images of a face they've seen before, while women recruit from both hemispheres — literally doubling the brainpower.
"Now, research from York University in Toronto has added a wrinkle to the existing wisdom. It's not just women whose brains are so nimble, the investigators have determined; it's gay men too."
Read more: http://www.time.com/time/health/article/0,8599,199...