<prompt> Most common ovarian tumour in less than 20 year old is:Epithelial tumourGerm cell tumourMetastatic tumourSex cord stromal tumour  <response>: Below 20 years, 60 ovarian tumours are of germ cell origin and in girls less than 105, 85 tumours are of germ cell origin. Ref: Shaw 15th edition: page; 376. 