full fat is for the calories really, babys need the calories, there isnt any less calcium betwen the semi skimmed and full fat its only the fat content that change its a myth.
it is actually the vitamin A and D.
when they are 2 yrs old they can go to semi skimmed,
https://www.eatwell.gov.uk/asksam/agesandstages/childrenandbabies/?lang=en#A219842
xx