In 2021, Fleischman co-authored the paper Can 'eugenics' be defended?, which argued that the scientific debate around genetic enhancement was polarized and concluded that "just as enhancement isn't a unified category that we can simply judge as morally good or bad, so too with genetic enhancement or eugenics". Fleischman wrote an essay in 2023, titled "You're Probably a Eugenicist", arguing that Dor Yeshorim's goal of reducing the rate of Tay-Sachs disease and cystic fibrosis in Jewish families could be described as eugenicist and that "Gay men and lesbian women in the US often use gamete donors from egg and sperm banks to have kids in a process that is transparently eugenic ... Organisations that recruit egg and sperm donors don't just recruit for fertility, they also screen for mental and physical health, height, education and criminal history – because that's what their clients want and expect".

Fleischman is a staunch advocate of polygenic embryo screening. According to historian of science Emily Klancher Merchant, Fleischman has claimed that "selecting an embryo according to its predicted educational attainment is no different from selecting one according to its number of chromosomes". Fleischman is quoted as saying "we are all eugenicists".