Consider a Riemann surface X of genus g ≥ 2 equipped with an antiholomorphic involution τ . This induces a natural involution on the moduli space M (r, d) of semistable Higgs bundles of rank r and degree d. If D is a divisor such that τ (D) = D, this restricts to an involution on the moduli space M (r, D) of those Higgs bundles with fixed determinant O(D) and trace-free Higgs field. The fixed point sets of these involutions M (r, d) τ and M (r, D) τ are (A, A, B)-branes introduced by Baraglia-Schaposnik [4].In this paper, we derive formulas for the mod 2 Betti numbers of M (r, d) τ and M (r, D) τ when r = 2 and d is odd. In the course of this calculation, we also compute the mod 2 cohomology ring of SP m (X) τ , the fixed point set of the involution induced by τ on symmetric products of the Riemann surface.