[andreyf]

This might be a strictly American "politically correct" interpretation, but I think your last sentence assumes that being Mexican and being an engineer is exclusive, which it obviously isn't.

[catz]

> but I think your last sentence assumes that being Mexican and being an engineer is exclusive, which it obviously isn't.

No it doesn't. I am sure that there are Mexicans from the whole spectrum of the population (doctors, engineers, manual labourers, etc...).

With highly skilled visas you can assure that you only get immigrants from a certain section of the population (Engineers).