▁and ▁writing ▁on ▁the ▁effect ▁of ▁h orm ones ▁and ▁the ▁central ▁nerv ous ▁system ▁on ▁growth ▁and ▁pub ert y ▁and ▁their ▁dis orders ; ▁the ▁function ▁of ▁the ▁human ▁sex ▁chrom os om es ; ▁and ▁dis orders ▁of ▁sexual ▁development . ▁ ▁Career ▁After ▁gradu ating ▁from ▁New ▁U tre cht ▁High ▁School ▁in ▁Brook lyn , ▁New ▁York , ▁and ▁then ▁att ending ▁Columbia ▁College ▁in ▁New ▁York ▁City , ▁Gr umb ach ▁went ▁on ▁to ▁ear n ▁his ▁medical ▁degree ▁from ▁the ▁College ▁of ▁Phys icians ▁and ▁Sur ge ons , ▁Columbia ▁University , ▁in ▁ 1 9 4 8 . ▁He ▁completed ▁his ▁intern ship ▁at ▁Mount ▁S ina i ▁Hospital ▁in ▁ 1 9 4 9 ▁and ▁his ▁res iden cy ▁at ▁Bab ies ▁Hospital , ▁Columbia ▁Pres by ter ian ▁Medical ▁Center ▁in ▁ped iat rics ▁under ▁the ▁direction ▁of ▁R ust in ▁Mc Int osh ▁in ▁ 1 9 5 1 . ▁During ▁the ▁Korean ▁War ▁he ▁served ▁as ▁a ▁captain ▁in ▁the ▁United ▁States ▁Air ▁Force ▁Medical ▁Corps , ▁with ▁assign ments ▁at ▁Oak ▁R idge ▁Institute ▁of ▁N uc lear ▁Studies ▁in ▁Tennessee ▁and ▁at ▁Fort ▁Det rick ▁Bi ological ▁Labor ator ies ▁in ▁Maryland . ▁Following ▁his ▁military ▁service , ▁Gr umb ach ▁did ▁a ▁fellow ship ▁with ▁Law son ▁Wil kins ▁at ▁Joh ns ▁Hop kins . ▁He ▁then ▁returned ▁to ▁Bab ies ▁Hospital ▁and ▁Columbia ▁University ▁in ▁ 1 9 5 5 , ▁becoming ▁found ing ▁director ▁of ▁the