Is Leonard Nimoy a member of the Cohen Jewish Priestly Family?

Leonard Nimoy is not a Kohen.

Wikipedia says:

The positioning of the kohen's hands during the Priestly Blessing was Leonard Nimoy's inspiration for Mr. Spock's Vulcan salute in the original Star Trek television series. Nimoy, raised an Orthodox Jew (but not a kohen), used the salute when saying "Live long and prosper."

See related link below.http://www.answers.com/topic/kohen#ixzz19s2LDZLG