To answer this question, we will make the punnet square. But firts, let us to make the following considerations:
1. The ability to taste PTC is a dominant trait.
Therefore,
2. The genotype of the dominant homozygous is TT and he/she is taster of PTC.
3. The other member of the couple must be homozygous, because she/he expresses the recesive trait. Therefore, the genotype of the latter member of the couple must be tt.
Now, let us draw the punnet square for this situation:
As you can see, in this case all members of the offspring are heterozygous and tasters of PTC.
