A modified human follicle stimulating hormone (FSH), which differs from the wild-type human FSH, said modified human FSH comprising an α-subunit and a β-subunit, said α-subunit comprising at least three basic amino acids in the α-subunit at positions selected from the group consisting of positions 11, 13, 14, 16, 17, and 20, wherein by human is meant the number of amino acid substitutions in the wild-type sequence does not exceed one-half the number of amino acid differences at corresponding positions in the FSH subunits between human and bovine species.