Why men can't multitask?

I don't know how I do it but I do manage to multitask every so often just like most of the women. Like earlier,  I was blogging, playing tetris battle in facebook and watching a concert show in my husband's cellfone which is so tiny. Now if it's in a big flat screen tv, mounted with one of those sophisticated mounting brackets it could have been easier.

And as I have said, I do manage and I'm glad I can do that. In the office, I multitask a lot, I answer phone calls and do emails at the same time. I can also be talking to you and listening to other conversations at the same time.

But it's entirely different with my husband and I wonder why? if he is doing something and then watch tv at the same time he'll sure forget the other one and get lost with the tv watching. He is always so focus, most of the time, I have to call him thrice or pat him just to get his attention.

A friend said her husband is also like that.
Now, is that a prof that men can't really multitask? and that men are incapable of doing more than one thing at once? Is there a scientific explanation on this? Is it proven?

I wouldn't really know why except that maybe because they are more focus which is also a good trait
but then, I do hope my dear husband will learn to multitask someday  to maximize the time :D