PGS Testing & Transfering

Hi there, I’m new here! My husband and I are moving forward with IVF. I am 36, low ovarian reserve and also have a chromosomal rearrangement (translocation carrier of Downs)so will definitely have to get PGS testing.

Curious to now why, even after the test and they have their healthy embryos (god willing we have more than 1..) do they usually only transfer 1? Wouldn’t they be ok transferring more than that since the testing has proven that they’re healthy embryos. I would be happy with just 1..and at this point “beggers can’t be choosers” but have always wondered about this. Thanks for the help!