The main findings of this study are as follows: (1) the offspring of mothers with STZ-induced diabetes had low nephron number, kidney injury, hypertension, increased ADMA levels, and decreased renal arginine-to-ADMA ratio; (2) ADMA impaired nephrogenesis and reduced nephron numbers in a metanephroi culture; (3) kidney injury, increased ADMA, decreased arginine-to-ADMA ratio, and decreased DDAH activity in the STZ group were reversed by maternal citrulline therapy. This evidence concerns the gene DDAH1 and diabetes mellitus.