Can PGT-A guarantee a healthy baby?

No, and it is important to be clear about how much it does not cover. PGT-A screens embryos for the number of chromosomes. That is all it does. It does not test for: Single gene conditions such as thalassaemia, cystic fibrosis or sickle cell disease, unless PGT-M is added specifically for a known condition in your family. Structural abnormalities of the heart, kidneys, brain, spine or limbs. Conditions caused by problems arising later in pregnancy. Autism, learning difficulties or most developmental conditions. Anything not chromosomal. Even for chromosomes, it is not a guarantee. The biopsy takes a few cells from the outer layer of the embryo — the part that becomes the placenta — not from the part that becomes the baby. Those cells usually reflect the embryo, but not always. ESHRE notes that chromosomal mosaicism, where different cells have different chromosomes, may lead to misinterpretation of the embryo's actual chromosome makeup. There is also a small chance of a straightforward error, which is why ESHRE recommends prenatal diagnosis is offered to all women who become pregnant after PGT. What PGT-A genuinely offers is a reduced chance of transferring an embryo with a chromosome abnormality. That is worth something. It is not the same as a healthy baby, and any clinic presenting it that way is overselling it.