According to a leaked document obtained by the New York Times, the Trump administration is considering a new nationwide definition of gender "on a biological basis that is clear, grounded in science, objective and administrable." Specifically, the definition would be applied under Title IX (which is used to prevent gender discrimination) and would be based entirely on genitalia at birth and/or genetic testing if a person disputes the definition. It is unclear from the leaked parts of the memo how the defintion would deal with intersex individuals.
The proposed definiton, if implemented, would essentially elimate any protections given to the approximately 1.4 million self-identified transgender people in the US. I think that even if one does not support transgender people (who I personally do support), the proposed change is pointless. All it will do is alientate intersex people and anger transgender people and their allies. However, as it is a leaked draft and not a full memo, there may be some motive that the Trump administration has that will be revealed.