Recently, I've heard a story about a woman who went through numerous rounds of IVF. Of her original eggs, she was down to the last two in the batch, both looked like poor quality and the doctors wanted to abandon the cycle and have her start stimming all over again. They really did not look good.
There were several other potential negative factors but I can't remember all of them. From a logical/medical perspective it looked as if this woman had everything against her She insisted the doctors continue on with the embryo transfer and well she had a healthy, thriving son.