PGT (pre-implantation genetic testing)

The forms of PGT, and the old names

The UK fertility regulator, the HFEA, describes PGT-M, “previously known as preimplantation genetic diagnosis” (PGD), as a treatment that “involves checking the genes or chromosomes of your embryos for a specific genetic condition.”

It describes PGT-SR as “a treatment that involves looking at the chromosome structure of your embryos, and finding where segments may have been deleted, duplicated or inverted.”

And it says “PGT-A (previously known as preimplantation genetic screening or PGS) involves checking embryos for abnormalities in the number of chromosomes.”

What it involves

Every form needs IVF: “Because the embryos need to be tested in a lab, you will need to have IVF, even if you and your partner have no fertility problems.” The test itself is a biopsy: “To perform PGT-A, embryologists remove a cell, or if at a later stage, several cells (a biopsy), from the embryo, which are then tested to assess the number of chromosomes they contain.” The HFEA says “PGT-A is now mostly carried out at the blastocyst stage on day five or six.” See blastocyst culture.

What India's ART Act says

This is where Indian law is specific. Section 25(1) of the ART Act: “The Pre-implantation Genetic testing shall be used to screen the human embryo for known, pre-existing, heritable or genetic diseases only.”

The Act defines PGD as “the genetic diagnosis when one or both genetic parents has a known genetic abnormality and testing is performed on an embryo to determine if it also carries a genetic abnormality”. Section 26(1) adds that “the clinic shall not offer to provide a couple or woman with a child of a pre-determined sex.” Ask any clinic that offers PGT-A how its testing fits within section 25(1).

What the regulator says about PGT-A

The HFEA lists PGT-A as a treatment add-on and publishes its own rating of the evidence. It explains why: “PGT-A is a selection tool that often reduces the number of embryos available for transfer.” It also notes “Sometimes, the result is reported as mosaic, which means the embryo contains both euploids and aneuploid cells.” Whether it is appropriate in a particular case is a clinical decision for the treating doctor. This directory does not make that judgement.

Questions

Is PGD the same as PGT?

PGD is the older name for PGT-M. The HFEA describes PGT-M as “previously known as preimplantation genetic diagnosis”.

Is PGS the same as PGT-A?

Yes. The HFEA says “PGT-A (previously known as preimplantation genetic screening or PGS)”.

Can PGT be used to choose a baby's sex in India?

No. Section 26(1) of the ART Act says “the clinic shall not offer to provide a couple or woman with a child of a pre-determined sex.”

Do I need IVF to have PGT?

Yes. The HFEA says “you will need to have IVF, even if you and your partner have no fertility problems.”

Sources

• HFEA, Pre-implantation genetic testing for monogenic disorders (PGT-M) and chromosomal structural rearrangements (PGT-SR), read 25 September 2026.
• HFEA, Pre-implantation genetic testing for aneuploidy (PGT-A), read 25 September 2026.
• The Assisted Reproductive Technology (Regulation) Act, 2021 (No. 42 of 2021), read 25 September 2026.
• The Assisted Reproductive Technology (Regulation) Rules, 2022, G.S.R. 419(E), 7 June 2022, para 10.1 (not changed by the Amendment Rules, 2026, G.S.R. 491(E)), read 25 September 2026.
• Clinic data: each clinic's own website, as read by this directory; registry level from the National ART & Surrogacy Registry extract.