Lots of militaries have looked at this. There is enormous ideological pressure on militaries to treat women the same as men, but unbiased studies always conclude that it would be a bad idea to do so. And no it's not the fault of the men's gallantry. Women are just physically weaker in ways that matter a lot for fighting. The idea strength in soldiers doesn't matter isn't believed by the military itself and the strange justifications in this thread don't have much basis in actual military doctrine (militaries aren't generally concerned with family planning...)
This report might be useful. It summarizes a large scale study done in 2002 by the British army. The tests were heavily rigged in favour of the women but even so the conclusion was to keep them out of combat roles. Note the part where they say that fewer than 2% of women were as fit as the average male soldier:
https://www.cna.org/reports/2012/Practices-of-Foreign%20Mili...
A panel of subject matter experts conducted the study. They issued a report, A Study of Combat Effectiveness and Gender, to British ministers in 2001.[24] The study's tests were designed to examine the feasibility of mixed-gender tank crews, all-women crews, mixed infantry units, and all-women infantry units. They also were designed to examine how men would react to the presence of women on the battlefield and how each gender coped with the physical demands of combat.
According to news articles, some reports maintain that the exercises found that women were as capable as men for service in combat units, but the results were mired in controversy [56]. Senior military officers, including Brig Seymour Monro (the Army's director of the infantry), stated that the Army field tests were so diluted that they “amounted to little more than aggressive camping.” Brig Monro also said that tasks that women were not physically capable of doing were simply dropped from the trials [56]. According to the final Ministry of Defence report, the study showed that fewer than 2 percent of female soldiers were as fit as the average male soldier [57].
Specifically, news reports stated that the trials stalled early on when women were not able to complete a number of tasks under battlefield conditions:
• When asked to carry 90 pounds of artillery shells over measured distances, women failed 70 percent of the time (compared with a male failure rate of 20 percent).
• When asked to march 12.5 miles carrying 60 pounds of equipment followed by target practice in simulated wartime conditions, women failed 48 percent of the time (compared with a male failure rate of 17 percent).
• Women were generally incapable of digging themselves into hard ground under fire.
• Women were generally slower in simulated combat exercises involving "fire and move" drills.
• Women suffered much higher injury rates in close-quarter battle tests, such as hand-to-hand combat.
