Doctors insist tiny Nmachi is not an albino and neither of the parents has any mixed-race family history.
Dad Ben Ihegboro, 44, a railway customer services adviser, said: "We both just sat there after the birth staring at her for ages - not saying anything.
"The first thing I said was 'What the flip?'."
Nmachi, whose name means Beauty of God in the Nigerian homeland of parents Angela and Ben, was born at Queen Mary's Hospital in Sidcup, Kent.
Doctors there told them she is not an albino.
"She doesn't look like an albino child anyway - not like the ones I've seen back in Nigeria or in books," Ben told The Sun. "She just looks like a healthy white baby."
Ben added: "Of course, she's mine. My wife is true to me. Even if she hadn't been, the baby still wouldn't look like that.
"We don't know of any white ancestry. We wondered if it was a genetic twist. But even then, what's with the long curly blonde hair?"
Professor Bryan Sykes, head of Human Genetics at Oxford University, said: "In mixed race humans, the lighter variant of skin tone may come out in a child - and this can sometimes be startlingly different to the skin of the parents.
"This might be the case where there is a lot of genetic mixing, as in Afro-Caribbean populations. But in Nigeria there is little mixing."
He said that both parents would have needed some form of white ancestry for a pale version of their genes to be passed on.
"The hair is extremely unusual," Prof Sykes said. "Even many blonde children don't have blonde hair like this at birth."