There are examples to back up the idea that cloned humans would be indistinguishable from ordinary folks. So-called “identical” twins share the same DNA but no one thinks that twins are less human than singletons. A clone would be even less like its source of genetic material than twins are like each other because a clone would grow up in a different environment.
Likewise, over 100,000 children have been born in the US as the result of in vitro fertilization, so it can’t be the manipulation of eggs alone that results in the ethical objection to cloning.
And it’s not the case that a clone would not have a mother, since babies still develop in wombs and gestation still takes about 9 months.
Last November, the UN issued a report that called for a global ban on human cloning. The authors’ opposition to human cloning is that clones might be denied full human rights. Brendan Tobin, one of the authors, has said that if cloning is not banned, then
“…the world community must accept responsibility and ensure that any cloned individual receives full human rights protection.”
It seems to me that there are no relevant features of a clone that would be grounds for denying human rights! But at the same time, human rights are sometimes denied to women, to children, to widows, to members of particular race, ethnic, or caste groups, and to the disabled, without any grounds.