By Kim Glovas

PHILADELPHIA (CBS) — New information from the U.S. Census indicates that the number of whites increased slightly in Philadelphia, while the number of blacks went down slightly.

Philadelphia’s population declined after 1950, as families headed for the suburbs for more space. But Dr. Janice Madden, a professor of sociology at the University of Pennsylvania, says that mainly applied to whites. Now, she says, blacks are heading for the suburbs because discrimination isn’t as much of a factor. Another factor, though, is family size.

“Family sizes are getting smaller, and people are just much less likely to have children, and the desire for space was often fueled by children. And as there are fewer children among whites and among African American middle class, too, there’ll simply be less demand for suburbs. Cities become relatively more attractive,” Dr. Madden explains.

Philadelphia’s white population rose by .7% between April 2010 and July 2011. The city’s African American population went down by .4% during the same time.