  We present a new mechanism for creating the observed cosmic matter-antimatter
asymmetry which satisfies all three Sakharov conditions from one common thread,
gravitational waves. We generate lepton number through the gravitational
anomaly in the lepton number current. The source term comes from elliptically
polarizated gravity waves that are produced during inflation if the inflaton
field contains a CP-odd component. In simple inflationary scenarios, the
generated matter asymmetry is very small. We describe some special conditions
in which our mechanism can give a matter asymmetry of realistic size.
