Answer:
2:1
Explanation:
Let the allele for achondroplasia be represented by A.
Since the disease is lethal in AA condition, the two people would rather be Aa.
Aa x Aa
offspring AA Aa Aa aa
The AA offspring does not survive, hence, we are left with 3 children out of which 2 are affected heterozygotes and the remaining 1 is a true-breeding recessive and normal.
The expected ratio of affected to normal offspring is, therefore, 2 to 1.
