For the purpose of this study, the investigators will perform the removal of trophectoderm (TE) the cells as required for the purpose of pre-implantation genetic screening, in order to perform the genetic analysis. Additionally, the investigators will remove the blastocoelic fluid (BF) and perform additional genetic analysis on the embryo in order to determine the agreement of the genetics results between TE cells and BF.

The human embryo (fertilised egg) develops from a single cell and goes through several developmental stages in order to prepare for implantation inside the womb. During the fifth and sixth day post fertilisation, the embryo becomes a blastocyst. It consists of 100-150 cells and has two cell types. The inner cell mass (ICM) will give rise to the baby and the trophectoderm cells will become the placenta. The trophectoderm (TE) cells surround the ICM. Following the formation of the two cell types, the TE cells start producing fluid. The progressive accumulation of fluid leads to the formation of a cavity that expands to form the blastocele cavity. This cavity contains fluid is known as blastocoelic fluid (BF). The fluid can contain proteins, cells and genetic material. Traditionally to make a genetic diagnosis or when to screen embryos for abnormal chromosome number, cells are removed (biopsy) from the trophectoderm. In experienced hands, this is a very safe procedure and causes minimal damage to the embryo. However, recent studies have shown that blastocoele fluid may contain genetic material which can be aspirated (drawn out) from the blastocole cavity (blastocentesis) and used for genetic analysis of an embryo. This is potentially less invasive and harmful to the embryo. The aim of this study is to compare genetic analysis obtained following blastocentesis versus trophectoderm cell biopsy.

Inclusion Criteria:

• Couples undergoing assisted reproduction for pre-implantation genetic diagnosis

Exclusion Criteria:

• Any other couples undergoing assisted reproduction