What exactly do seats with a cut out in the middle achieve? I've read that seats with a cut out are a good way of relieving stress on your sensitive areas. So we have seats like this:



My question is: from what I've read, the problem with cycling with bad seats is that it puts pressure on your perineum. This is the part that carries the nerves to the penis and testes -- but the cut out, which is in the middle will in no way reduce pressure on the perineum, which start off perpendicularly from a line joining the sit bones. So if you sit on the widest part of the seat, the perineum won't lie on the cut-out. As in:



Our intention is to protect the perineum; so I'd wager that a cut out in the middle doesn't solve that problem at all. 

[I understand that this particular example of a saddle does seem to have some sort of a depression where the perineum would lie -but it's still not perfect, and my question also concerns the use of the cut out in the middle.]
The depressed channel running down the middle of the saddle is what is taking pressure off the perineum, not the actual hole in the middle. Some saddles merely have the channel with no actual hole.