For example , in the 1950s , scientists at the Karolinska Institute in Sweden propagated a polio virus in fetal cells to make into a polio vaccine .
One of the first medical applications of fetal tissues was their use in the production of the first polio vaccines .
In the 1950s , scientists at the Karolinska Institute in Sweden propagated a polio virus in fetal cells to make into a polio vaccine .
One of the first medical applications of fetal tissues was their use in the production of the first polio vaccines .