Transgender soldiers would have their sex hormones changed to to that of the opposite gender, which would cause many changes in their bodies.
Under this therapy, both sexes would gain what's known as the secondary sex characteristics of the opposite sex, which is the sexed outward appearance a man or woman has
[1][2].
MtFs would naturally gain female breasts
[3].
FtMs would experience less positive and negative emotions, like men do
[4].
MtFs would also get various emotional changes
[4].
MtFs would gain a smaller muscle mass like a women has
[3],
and FtMs would gain an increase in muscle mass
[5][5.5].
MtFs would get a reduction in body hair like women have
[3]
and FtMs would get an increase in body hair like men do
[5].
MtFs develop emotional fluctuations from fluctuating estrogen, like a woman gets during a period. FtMs develop a more masculine brain
[6],
and FtMs develop a more feminine brain
[6].
MtFs become so much weaker that the international Olympic organization have allowed trans women to compete since 2004
[7].
However not a single trans woman managed to qualify for any women's sport in the Olympics since those 12 years. There was one athlete, a cyclist named Kristen Worley, who came close to qualifying for the Olympics, but the cyclist failed to reach the minimum speed requirements for qualification as an Olympic cyclist
[8].
Logically, a trans woman is simply not as physically capable as a man, and trans men strength similiar to a man. After doing proper testing, the military should put transgender people in the roles that match their physical capability.