In this journal, Zipple (2020, p. 135) defined the ‘Bruce effect’ as ‘a phenomenon by which females terminate existing reproductive investment, either through blocking of implantation or through pregnancy termination, following nontraumatic exposure to nonsire males’. He and his collaborators have used the same or a similar definition also in other articles (Zipple, Roberts, Alberts & Beehner, 2019, 2021). In the most recent paper Zipple et al. (2021) challenged attempts to maintain the original definition for the ‘Bruce effect’ as the failure of blastocyst implantation in a female exposed to a nonsire male or his odour (Barto_s, Du_sek, Barto_sov_a, Pluh_a_cek, & Putman, 2021).