López S, Meirelles J, Rayol V, et al. Gene doping and genomic science in sports: where are we? Bioanalysis 2020;12(11):801-811. https://www.researchgate.net/publication/342325121_Gene_doping_and_genomic_science_in_sports_Where_are_we
an interesting question. And despite the reality that gene doping is already around and used as mentioned by Govindasamy and Martin, your question is more complex. In short: we know that diet and physical exercise can cause genetic imprints, in terms of epigenetic changes. These do not affect DNA seqeunce but the chemical modification of DNA. It is also know that these changes are heritable and may effect children of the athletes and maybe also later generations. However, it is currently largely unknown which type of doping would cause which epigenic change, how long it would reside and if these changes are detremental or beneficial. This is of course also due to the fact that most doping cases are not made public. Currently, research focusses on the epigenetic effects of regular physical exercise but this is still a field with many open questions. Maybe to start with, have a look at
Article Impact of Physical Activity and Doping on Epigenetic Gene Regulation
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