These are policy ideas, consideration of which could lead us directly into politics.
On an historical note in WW2 women in the UK were effectively drafted although they often had a choice of service arm to join. Approximately 200,000 chose to join the ATS or were compelled to do so. Duties included administrative tasks, motor transport* and serving AA guns in 'mixed' AA batteries. They performed all roles other than No.1 I think it's called. That is they were forbidden to actually fire the gun, thus they could retain their non-combatant status they had from their Axiliasry status to fully accepted members of the armed forces thus justifying their wage rate of 66% of male equivalent. Casualties 329 dead I believe out of 70,000 or 200,000 So 66% of full pay seems reasonable to me.
I believe that mixed batteries employed somewhere between 35,000 and 70,000 women, their role in shooting down V-1s in the months after D -Day being particularly notable** 51 mixed HAA regiments eventually formed. Numbers include searchlight operators.
The all-male draft was challenged all the way to the Supreme Court in 1981 on the basis that such single sex draft was illegal or unconstitutional after the passing of the Equalities Act. The organisation most prominent in funding the challenge was the National Organisation of Women.
Women are increasingly taking on combat roles in many countries.
Given that voluntary background and the equality agenda since WW2 I can't see an All Male draft washing in the UK or US. Women would not stand for it. I think that s the direction you are going in if you put restrictions on women's employment
* you may recall that our current Queen, Elizabeth Windsor, Ezabeth I by the grace of God etc was in the ATS as a motor mechanic Princess oily rag - straight up.
**when male crewed batteries departed for France (including 2x 90mm American Regiments which were particularly well equipped and trained).
A bibliography and source
http://americanhistoryprojects.com/downloads/ww2/combat.pdf
https://history.unt.edu/sites/history.unt.edu/files/users/dsg0009/anti_aircraft_bib.pdf (for sourcing, i have not read this list)
Principal root refrences for numbers of women in Anti Aircraft Command 16. General Sir Frederick Arthur Pile, Ack-Ack (London, 1949), 186; See also J.W.N., "'Mixed' Batteries," Journal of the Royal Artillery 69 (1942): 199-206
The service for many was brief, just the V-1 crisis 4 months. Mixed regiments were shut down fairly quickly as men cleard the V-1 launch sites in Norterrn France.
additional site for numbers of mixed units
Northumbrian Gunner: National Arboretum - ATS Ack Ack Girls Memorial
General Reference
Gunfire! British Artillery in the Second World War Stig H. Moberg
Ubique: The Royal Artillery in the Second World War Richard Doherty