Chevy, I have read a little bit on blasto as i had to blasto cos i wasn't well for ET on day 3. I lost 4 good grade embryos in doing that which im still feeling sour. my doc didn't like the idea of blasto but that was the best option for me at that time. im still upset losing 4 embryos but subsequently i read that if embryos can't survive to blasto, it less likely it will survive in our womb too. in some clinic, they only do blasto trsf as they think that to do D3 trsf is to pass the responsibilities back to patient asap and also to ensure they make $ from ET. I don't know, if i were you, with just 5 snowbb, I will not blasto cos the success rate is only 40% according to my embryologist. And to a certain extent, mother nature has to be better than man made environment. To a great extent, we rely on the embryologist skill in blasto and im being skeptical .... but we really don't know if sometimes, they would experiment with our embryos esp when they know we have a few for them to "play" with... Giving them the benefit of doubts, i don't think they would but we never know.......