After finding this news and reading the original journal paper, few things came to my mind:

Accordingly to the summary of published report in the journal Cell [1], authors say “We found that Injection of H3K9me3 demethylase Kdm4d mRNA and treatment with histone deacetylase inhibitor trichostatin A at one-cell stage following SCNT greatly improved blastocyst development and pregnancy rate of transplanted SCNT embryos in surrogate monkeys. For SCNT using fetal monkey fibroblasts, 6 pregnancies were confirmed in 21 surrogates and yielded 2 healthy babies.”

Genetic analysis was done to confirm the origin of monkey from the original donor cell and egg of monkey.

Some Interesting Statistics:

In this study, total of 63 female monkeys were used as test surrogates. Out of 63 surrogates receiving SCNT embryos, only 28 became pregnant (44.5% success rate). Out of 28 pregnancies, only 4 resulted in live births, where only 2 offspring survived. That is only a 7.1% success rate within the sample and 3.17% success rate in the whole population of 63 female monkeys used as test surrogates. In other words, the way this study was designed, the overall SCNT success rate was only 3.17%!

Ethical issues:

It would be almost impossible to do this kind of study (N = 63 total monkeys) in the U.S due to ethical issues. There are several viable alternatives to using monkeys for SCNT research. It may be simply that doing research on monkeys is easier in China and do not require stringent approval and justification. Moreover, since the SCNT embryo transferring method works on monkeys, it will likely work on humans too! It common for us to think: will it ever be tested on humans?

[1] http://www.cell.com/cell/fulltext/S0092-8674(18)30057-6