Many members of the large family of transforming growth factor-β (TGF-β) proteins have fundamental roles in reproduction. For example, activins and inhibins regulate follicle stimulating hormone (FSH) production by the anterior pituitary; oocyte-secreted GDF-9 and BMP-15 control follicle maturation and ovulation rate; and AMH is a negative regulator of primordial follicle activation. My research focuses on four aspects of reproductive TGF-b ligand biology: (i) synthesis and activation; (ii) species differences; (iii) mutational effects; and (iv) therapeutic utility. Based on my understanding of the structure/function of these ligands, we have recently used the CRISPr/Cas9 system to generate inhibin and activin knockin mice. These novel models will enable the long-term characterization of the reproductive and endocrine actions of these molecules. A thorough understanding of the physiology of these ligands then directs our therapeutic approach, which is focused on developing inhibins to treat postmenopausal complications and GDF9/BMP15 analogues for the treatment of infertility.