QUOTE(Cyrilla @ Mar 30 2011, 11:32 PM)

QUOTE(MusicalNitWit @ Mar 30 2011, 08:14 AM)

My other son sat such a test when he was younger and got the highest score that the school had ever seen, and this was at a choir school. However, he is average on his only instrument and cannot sing at all - he is the small percentage of people that genuinely cannot sing!
I haven't ever met anyone who 'genuinely cannot sing'...

I think in theory everyone can, that is, if they have a set of bellows, a larynx and a functioning mouth cavity.
However, in practice the combination of
(a) retarded development of the ability to coordinate the sound in your "mind's ear" with a sound from your larynx - which is further retarded if you don't get any practice at it
(b) being able to "get" the physical sensation of the singing voice as opposed to the speaking - regardless of pitching ability
© extreme inhibition based on the awareness of (a) and (b)
results in there being, alas, not a few people who can't sing in any meaningful sense of the word.
It can be done. But in some people it takes a lot of time. I did have a succession of young men at one stage who wanted to come for lessons - one, alarmingly, was already, so he told me, doing gigs with a band! - but found great difficulty in pitching accurately either against a piano or against my voice, in whatever octave. Most of them decided that as they were not as good as they had thought, they would cut their losses and do something else.
One did stay for about four lessons, though. He knew it was going to be hard work, and said he was determined to get there. In about the third lesson, I had him on Hey Jude (because he said he liked it)
He managed the first two notes at the right pitch. We could always work on improving the sound quality later. He sang the third note at the same pitch as the first, instead of the second, as it should be. I did quite a lot of work getting him to copy me, draw diagrams with his fingers, etc, sing so-mi-mi and so on.
Then he started again. So-mi-so...
"Oh no," he said "it's going up again, I can hear it"
That was a bit of a revelation to me, as I had thought up until then that everyone "thought" the note they were going to sing before pitching it. Since that time, I have come to realise that there are many people who pitch without aiming first, and only know if it's right when they hear what comes out.
It's do-able. But as this lad was 24 and hadn't done any before, it was going to take a very, very long time, and a lot of intensive work. I think he was wise to decide he had other musical priorities.
Start them young, in school! Make sure the nursery and reception and year one teachers are not singing in a half-speaking voice way below middle C! Or they'll end up like poor old whatisface that I was describing up there.