  We report the results of VLT and Keck adaptive optics surveys of known
members of the Eta Chamaeleontis, MBM 12, and TW Hydrae (TWA) associations to
search for close companions. The multiplicity statistics of Eta Cha, MBM 12,
and TWA are quite high compared with other clusters and associations, although
our errors are large due to small number statistics. We have resolved S18 in
MBM 12 and RECX 9 in Eta Cha into triples for the first time. The tight binary
TWA 5Aab in the TWA offers the prospect of measuring the dynamical masses of
both components as well as an independent distance to the system within a few
years. The AO detection of the close companion to the nearby young star Chi^1
Orionis, previously inferred from radial velocity and astrometric observations,
has already made it possible to derive the dynamical masses of that system
without any astrophysical assumption.
