  (Abridged) An anisotropic theory of MHD turbulence with nonvanishing
cross-helicity is constructed based on Boldyrev's alignment hypothesis and
probabilities p and q for fluctuations v and b to be positively or negatively
aligned. Guided by observations suggesting that the normalized cross-helicity
and the probability p are approximately constant in the inertial range, a
generalization of Boldyrev's theory is derived that depends on the three ratios
w+/w-, epsilon+/epsilon-, and p/q. The theory reduces to Boldyrev's original
theory when w+ = w-, epsilon+ = epsilon-, and p = q.
