PGS test and grades

Hi, I had 12 mature eggs, 10 were fertilized and 5 made it to blastocyst, after PGS testing I have only 2 normal embryos. One boy and one girl, the boy is a 5AB and the girl is 4BB. I have a son conceived naturally and he is 4 years old, now that I know that I have a boy and a girl I want to choose the girl but the boy has a higher grading... I don’t know which one to transfer? And I also feel bad 😢 to have to choose between ny two embryos. Which Embryo did you choose to transfer? It was based in the quality or the gender?