Some units only recruit children of internal employees. Is this reasonable?

It is not necessarily unreasonable, it mainly depends on whether the unit has the autonomy to work. Some units, such as private enterprises, may decide to recruit only the children of internal employees. Some state-owned enterprises and institutions may also recruit among the children of internal employees for temporary employment for internal management. For state agencies, temporary workers can also be recruited internally. However, those who are involved in the establishment of enterprises, institutions and state agencies, such as civil servants, workers, public service personnel, etc., and who need financial support should be openly recruited from the public.