The function of ENSG00000073737 (DHRS9, dehydrogenase/reductase 9) is as follows. 3-alpha-hydroxysteroid dehydrogenase that converts 3-alpha- tetrahydroprogesterone (allopregnanolone) to dihydroxyprogesterone and 3-alpha-androstanediol to dihydroxyprogesterone (PubMed:11294878, PubMed:29541409). Also plays a role in the biosynthesis of retinoic acid from retinaldehyde (PubMed:11304534, PubMed:12618084). Can utilize both NADH and NADPH. {ECO:0000250|UniProtKB:Q8VD48, ECO:0000269|PubMed:11294878, ECO:0000269|PubMed:11304534, ECO:0000269|PubMed:12618084, ECO:0000269|PubMed:29541409}.