blastocysts

A couple is lucky to end with 5 implantable blastocysts at the end of multiple rounds of egg extraction, fertilization, and cultivation.

You mean the leftover blastocysts that are otherwise disposed as medical waste after IVF treatments?

The morning-after pill acts similarly in that it interrupts ovulation but additionally prevents any blastocysts from implanting, yes.

Frankensteining together human stem cells and monkey blastocysts until something works is pretty far from surgically selecting specific genes.

Blastocyst Injection: The selected ES cells are then injected into mouse blastocysts, which are early-stage embryos.

The recipient had one in-vitro fertilisation cycle 4 months before transplant, which yielded eight cryopreserved blastocysts.

Most doctors now do 5-day blastocysts, and insert only 1-2 (many insurance companies will only cover 1 at a time).

The survival rate is different because of the way they blastocysts have to be implanted.

Embryonic stem cells only come from four to five day old blastocysts or younger embryos.

And of course the cells will be tested to ensure each chromosome is normal and blastocysts that are defective are discarded.

For women above 35 years old, the percentage of viable blastocysts goes down (e.g.

A very large number of zygotes/blastocysts survive until implantation, upwards of 50%.

You get a "optical selection" of the most well developed blastocysts, checking for symmetry, growth rates, and other biomarkers, without even resorting to DNA sequencing selection.

When 200 ng/ml donor DNA was used, 75% (936/1,262) of the injected zygotes developed to blastocysts, 9% (86/936) of which were mCherry-positive (Figure 2C; Table S1)." So efficiency is inversely proportional to toxicity, they treated many more than 5-25 cells (the selection would occur at the level of the embryo), and there was only 1-10% rate of mutation detection.