Not necessarily. Intelligence is in big part determined by genetics.

No, IQ is extremely hereditary.

The heritability of IQ is often estimated at 0.4 according to Wikipedia. Not very high, but not insignificant. Height has 0.8 heritability.

Even if you're a genius, it doesn't mean your child will be. I think 0.4 suggests environmental factors are more important.

It's 0.4 in childhood, rising to 0.7 to 0.8 in adulthood.

Saying that you can adopt a child and raise him to be smart is approximately as foolish as claiming you can adopt a child and raise him to be tall.

Nope it's .75. IQ heritability is only .4 for children but it climbs to .75 as the children age into adulthood adults. So it's basically as heritable as height.

Wikipedia Quote

"The general figure for the heritability of IQ, according to an authoritative American Psychological Association report, is 0.45 for children, and rises to around 0.75 for late teens and adults"

You're assuming that any child I adopt would be genetically predisposed to lower intelligence than a child I would biologically have. That's not necessarily the case.

It's actually not that simple for adopted childen, unfortunately...