Four weeks after conception, the embryo that would become Corina was producing half a million neurons every minute.

But it tests fewer than half of the chromosomes in an embryo, so it's not a perfect indicator of overall embryo health and it hasn't been all that useful for most women.

Full quality of basic media were more suitable to callus subculture than half quality of that. But MS basic medium was advantageous to plant regeneration of mature embryo.