Not true, and verified.
www.spiegel.de/.../wwii-g-i-babies-children-of-the-enemy-a-456835.html
Something like 100,000 to 120,000 babies were born in Germany in the period 1945- 1949 by unwed mothers, fathers occupation troops. Roughly 50,000 to 60,000 each either Allied fathers or Russian fathers.