Number- and weight-average molecular weight of condensation polymers formed in the mixture of primary molecules carrying different species of functional groups A and B are derived by the cascade theory. These functional groups are allowed to form multiple junctions of arbitrary multiplicity k. From the weight average, the gel point condition is found to be given by 1 - (f(w) - 1)((μ) over bar (A,A) - 1) - (g(w)- - 1)((μ) over bar (B,B) - 1) + (f(w) - 1)(g(w) - 1) Dmu = 0, where f(w) and g(w) are average functionality of the primary molecules, (μ) over bar (alphabeta) the average multiplicity of beta groups in the junctions where a path of an alpha-group enters, and D-mu ((μ) over bar (A,A) - 1)((μ) over bar (B,B) - 1) - (μ) over bar (A,B)(μ) over bar (B,A) the multiplicity determinant. Possible applications to thermoreversible gelation are suggested. (C) 2003 Wiley Periodicals, Inc.