 Our pilot studies suggest that the form and route of estrogen are important determinants of estrogen effects on growth 2, 7. We recently found that very low doses of parenteral IM depot estradiol E2 together with recombinant growth hormone GH to Turner syndrome patients as young as 12-12.9 years of age produced a significantly greater adult height than standard doses of oral conjugated estrogen at this age 7. Thus, very low doses of the natural estrogen estradiol, E2 administered into the systemic circulation seem optimal for growth stimulation. 