def pairsAgreeGender(mp):
    """ Selects the minimal pairs that agree in gender, i.e. 
    the pairs with two entries of identical gender.
    For example amis (masc) / tamis (masc) is kept. """
    dropouts_1 = list(mp.loc[(mp.genre_1 == 'm') & (mp.genre_2 == 'f')].index)
    dropouts_2 = list(mp.loc[(mp.genre_1 == 'f') & (mp.genre_2 == 'm')].index)
    pairs = mp.drop(list(set(dropouts_1 + dropouts_2)))
    return pairs