Earlier this year, women over 55 were identified as the fastest-growing demographic on Facebook. Now it looks like they’re going in reverse.

During April and May, the number of U.S. Facebook users over 55 actually dropped by 650,000 after increasing by 1.6 million the prior two months, according to data from the Inside Facebook blog.

What’s behind the drop? In our house, our high schoolers have been perturbed to find their parents and grandparents snooping on their Facebook activities. Other pundits suggest that Facebook’s introduction of a real time stream in March with more frequent updates may not have been to their liking.

Women still represent the majority of Facebook users at 56 percent, with more women than men in every age bracket.