My argument for females to have a year off to take care of newborns (or so) was biologically based, focused on the interaction between natural selection and psychological developmental trajectories. I haven't seen any research on the history of natural selection across multiple people groups / genetic lineages that suggests the equivalent selection pressures have existed in the past for males.

One might insist on equivalent policies for the biological sexes on ideological grounds, e.g., men's rights, which is perfectly fine. However, from a logical perspective, arguing for males to have time off for the first year is jointly dependent on the biological argument (which applies to females) AND the ideological argument. Alternatively, from an empirical perspective, the research around males may exist and I am simply not aware of it.