Legal basis
Gender-equitable language has been a requirement for the public sector in NRW since 1999 in Section 4 of the NRW State Equality Act and was revised in Section 5 with the amendment of the Act in 2016:
Laws and other legal provisions shall take account of gender equality in terms of language. The equal linguistic treatment of women and men must be observed in internal and external official communication. Gender-neutral personal designations are to be used in forms. If these cannot be found, the female and male language forms are to be used.
Universities are therefore legally obliged to use gender-equitable language in all written correspondence and all written formalities. This also applies to the design of websites and other public relations materials. However, even in the area of teaching and informal communication, you should attach importance to gender-equitable and therefore accurate language that is appropriate to the university environment for the reasons mentioned above.
Since December 22, 2018, it has been possible for people who do not classify themselves as either female or male to have their positive gender entry entered diversely in the civil status register (PStG § 22, para. 3). The State Equality Act does not currently offer any explicit protection for people outside the gender binary. However, the General Equal Treatment Act stipulates that job advertisements must also be explicitly addressed to people with the gender entry diverse, at least with the addition "(m/f/d)" in the job title.
As diverse people are not mentioned in the legal text, it is all the more important to highlight them in everyday language and not to reinforce their marginalization. One way of doing this is to use the gender star.