A lawsuit was filed against the government Tuesday on behalf of nine children born in Japan to Japanese fathers and Filipino mothers who are seeking to be recognized as Japanese, according to their lawyer.

The children, aged 5 to 11, have lived their entire lives here and speak only Japanese. While all of them are legally acknowledged by their fathers, none of their parents is married.

"Forms of families and parent-and-child relationships are diverse," lawyer Hironori Kondo told a news conference after the suit was filed. "These children should be given Japanese nationality by nature."