They might be siblings, but the genetics are not the same. There is a lot of variation possible, especially with first generation crosses ad polyhybrids.
Do you have a brother or sister? I'm guessing you don't look exactly the same either haha.
It's normal for 2 plants of the same strain to look a bit different from each other. That's why i always use clones with no variations in pheno type or nutrient uptake. For some reason i always have problems while using seeds seeing every plant has different need and grows differently.
There is a wise saying in Spanish: El hijo de mi hija es mi nieto, pero el hijo de mi hijo...quien sabe?
The son of my daughter is my grandson, but the son of my son...who knows?