I know this is from the linked NYT piece, but I don’t think this is a helpful framing for UBI. Reparations is defined as “the making of amends for a wrong one has done, by paying money to or otherwise helping those who have been wronged.” If only past mothers received UBI, it could be appropriate, but it also helps future mothers, as well as everyone else. UBI, if given equally to all, is not reparations.
That said, reparations in the form of UBI enhancements for groups persecuted by past laws (e.g. blacks, Native Americans, maybe Asian Americans, even women), is an discussion worth having. But equal UBI will be an effective start at addressing historical injustices.