The controversial add-on that promises to improve IVF

At age 42, Amy Klein had already suffered three miscarriages and gone through several rounds of IVF. She wasn't done trying to have a baby. But she worried that her age likely meant that her eggs had chromosomal abnormalities that kept her from getting pregnant.

So starting in 2012, the health reporter opted for a controversial addition to the fertility toolkit: She went through four rounds of additional egg retrieval, and had those embryos frozen and genetically analyzed for abnormalities.

The basic in vitro fertilization (IVF) process kick-starts embryo formation by fertilizing an egg, or many, with sperm in a petri dish. Klein's plan was to add an optional and costly method called preimplantation genetic testing (PGT), to look for the most viable embryos in the bunch. Once the embryo reaches a stage called a blastocyst, technicians take a handful of cells-six or seven, about-to test them for genetic abnormalities that could result in disease or miscarriage.