Keeping ethnic Russians Russian

According to the Christian Science Monitor, Russia has slammed a bureaucratic door on foreign-based adoption agencies. The article posits anti-Americanism as a reason. However, they hint at an underlying rationale.

For US adoptive parents, Russia ranks third (after China and Guatemala) as the country of origin for the most orphans adopted. American families adopted 3,706 Russian children in 2006, down from 4,594 and 5,865 in the past two years...
A year ago, there were 89 accredited foreign-based adoption agencies; this week, the last of them saw their accreditation expire...
Kremlin-sponsored efforts to increase adoptions by Russian families are beginning to work, some experts say. For the past two years the numbers of domestic adoptions have exceeded foreign ones, though both combined remain a tiny sliver of the total number of Russian orphans.

Nationalists could not be sponsoring Kremlin-backed action against foreign-based adoption agencies to embarrass Putin, as Kremlin backing implies that consent on the part of Putin, given his successful concentration of power. Instead, the more like rationale is Putin is acting to stem the population decline in ethnic Russians, as he promised last year.

Russia's postcommunist demographic woes ... have become such a hot topic of late that President Vladimir Putin made it his highest priority during his May 10 state-of-the-nation address...
Fears over potential consequences are wide-ranging -- that the country won't be able to generate enough young men to fill the ranks of its military, that the economy will not be able to sustain itself, and that immigration could drastically alter the country's ethnic and religious makeup...
... Putin prioritized the steps the state must take to rectify the problem.
"First a lower death rate; second, and efficient migration policy; and third, a higher birthrate," Putin told the nation during his address.

Therefore, keeping Russian children out of the hands of American adoptive families is surely being framed as a matter of national security. Blocking foreign adoptions dovetails right into "migration policy".