Surveys have been done that show which states would be likely to vote Democratic or Republican if only women or men were voting in the Presidential election.
If only women were voting, the Democrats and Hillary Clinton would win a total landslide in the Electoral College, 458-80, with only the following states supporting the Republicans and Donald Trump:
West Virginia
Kentucky
Tennessee
Arkansas
Alabama
Mississippi
Louisiana
Oklahoma
North Dakota
Nebraska except for one electoral vote in the Omaha area
Wyoming
Idaho
Utah
A total of 13 states!
If only men were voting, the Republicans and Donald Trump would win a smaller landslide in the Electoral College, 350-188, with the following states supporting the Democrats and Hillary Clinton:
Vermont
Massachusetts
Connecticut
Rhode Island
Maine–only one electoral vote from Portland, Maine area
New York
New Jersey
Maryland
Delaware
District of Columbia
Illinois
New Mexico
California
Oregon
Washington State
Hawaii
A total of 15 states plus DC!