Two [men] who betrothed two women, but when they entered the bridal canopy they confused one with the other —- they are obligated [to bring a sin-offering] because of adultery; if they were brothers —- because of [the prohibition against] a brother's wife; if they were sisters —- because of [the prohibition against] a wife's sister; if they were menstruants —- because of [the prohibition against] a menstruant. We separate them for three months in case they are pregnant; but if they were minors incapable of childbirth, we restore them immediately. If they were the daughters of Kohanim, they are disqualified from [eating] terumah.