Even if you have day 5 embie transferred, it doesn't even guarantee you a successful pregnancy. We got lucky to have DH sperms but the only two 5 days embies ended up in chemical pregnancy. They all think is DH lousy sperms. People produce millions and he has like 3--5! I'm using DS. Yes, just like Bertie said, a lot of tears and heartache. I'm also preg. First go using DS (very lucky). So good sperm does make a difference.