Question

How can two parents without hitchhiker's thumb have a child who does have hitchhiker's thumb

Answer 1

That Trait (Hitchhiker's thumb) may be recessive in both the parents but when they transmitted their genes to their offspring, it became dominant in that 'cause of two similar genes (Homozygous Condition).

Hope this helps!

Answer 2

Provavelmente. Eu realmente não tenho feito muita Ciência ultimamente!!!!!!!