## Did you know that...

...the methods of genetic engineering have already been used to edit human genes? Despite the loud criticism from the majority of professional public, in 2018, in his laboratory, the Chinese doctor He Jiankui and his team genetically modified two human embryos. After these embryos were implanted, twins Lulu and Nana were born – the first people with a gene modified by genetic engineering techniques. Specifically, it was a modification of the CCR5 gene, which encodes a receptor involved in HIV infection. The modification should ensure increased resistance of the modified cells to infection, making it easier for the twins to live in a part of the world where HIV is a threat. However, almost the entire scientific community, ethical commissions of scientific institutes, and the lay public objected to this procedure. The reason for that is simple: no matter how good the original intention may have been, such an intervention in the human genome can have unpredictable consequences for the girls. This is because we still do not perfectly know all the processes in which the CCR5 receptor is involved, nor can we be completely sure whether some unexpected event did not take place in the editing process that could cause Lulu and Nana health problems in the future. The case of these two sisters is a reminder to all of us that the methods and technologies of genetic engineering must be handled with utmost caution and in accordance with international ethical standards. In conclusion, we will only add that at the time of writing this text, both girls are healthy and happy.