Growth and reproductive development are closely co-ordinated during puberty but there is also evidence that growth hormone (GH) may have a physiological role in adult ovarian function. Both GH and the insulin-like growth factors (IGFs) have been shown to augment granulosa cell proliferation and steroidogenesis in the human Graafian follicle, suggesting that GH may act as a 'co-gonadotrophin' at ovarian level. Furthermore, the intra-ovarian 'IGF system' (i.e. IGFs and IGF-binding proteins) may be implicated in folicular atresia and in disorders of follicular function associated with polycystic ovary syndrome (PCOS). The clinical importance of GH to ovarian function in the adult is illustrated by the finding that adjuvant GH treatment reduces the dose of exogenous gonadotrophin which is required to induce folliculogenesis in women with hypogonadotrophic hypogonadism. There is, however, no evidence that GH supplementation is of significant clinical benefit in the management of patients with other ovulatory disorders--including PCOS--or in superovulation protocols for in vitro fertilization.