  We consider the implications from the possibility that the recently observed
state X(3872) is a meson-antimeson molecule. We write an effective Lagrangian
consistent with the heavy-quark and chiral symmetries needed to describe
X(3872). We explore the consequences of the assumption that X(3872) is a
molecular bound state of D^{*0} and anti-D^0 mesons for the existence of bound
states in the D^0-anti-D^0 and D^{*0}-anti-D^{*0}.
