LuvBug - Yes they'll put DH's "boys" into the petrie dish/es and see how many fertilize overnight. There "may" be some that aren't mature (meaning no egg in the follicle) so that will reduce my fertilization rate. So even though I got 24 I might only have 15 (still a large amount) that actually fertilize and be classed as embrios.
So they will let them grow for the next 5 days to get as many to blastocyst stage and then freeze any left over or are good enough to freeze.
Quick rundown on my last EPU:
Retreived 15 at EPU
9 fertilized (so we lost 6 being either immature or just plain crap eggs)
Grew them out to 3 days
TF 2 embrio's that were grown to 3 days
Froze 4 (so lost another 3 due to crap embrio's)
My first EPU we did half IVF and half ICSI. IVF is where they put egg and sperm together in a dish and let them fertilize themselves. ICSI is where they inject sperm into the egg. We have good fertilization rates so we didn't do half half this time.
HappyKat - Your FS will be super conservative IF you do IVF. They usually treat the first cycle as a trial and error to see how well you respond to all the meds. You'llbe highly monitored through out. Multiple dildo cams, BT's etc..
I was threatened on a few occasions on my first cycle to be cancelled due to OHSS. FX you won't need to go that path though.