This paper focuses on the use of English epicene pronouns in discourse which most individuals are exposed to on an everyday basis. Gender-based linguistic reforms have been implemented since the beginning of the 1970s, to achieve a more non-sexist language. In the present study Corpus linguistics has been applied to investigate the use of personal pronoun he and the personal pronoun singular they in relationship with these linguistic reforms. The present study uses data from both written and spoken English between the 1930s and 2019. The data is collected from corpora COHA and COCA to diachronically study patterns of the use of generic he and singular they when used as anaphoric reference to an antecedent of unknown gender. To narrow the searches in corpora, indefinite compound pronouns are used in collocation with the epicene pronouns as linguistic features. Systematic sampling and mapping of the data lay the ground for the analysis that determines if patterns in the language can be related to the gender-based linguistic reforms. The evidence from the data collected for the present study shows that there are changes in use of male biased pronouns before and after the gender-based linguistic reforms. From the data conducted for the present study the evidence shows trends in the figures that the neutralization strategy can be related to the changes, to some extent. The diachronic development is discussed in connection with reforms, guidelines and previous conducted studies in more detail and suggestion on further studies are presented.