I suggest you would not like the side effects.
Right now, in both India and China, the combination of ultrasound and easy abortion is creating a ballooning demographic imbalance. Estimates of 30M unemployable males with no possibility of marriage, is growing faster than predicted, and 50M or more may be more accurate.
However, the threat of that many “excess” males is genuine. On their own, they will invariably destabilize their nations. Organized, they can turn into immense armies overnight.
This is especially dangerous in China, where a charismatic leader caused the Taiping rebellion, perhaps the second bloodiest conflict in human history after WWII, and which lasted from 1850 to 1864. Some of the battlefields of the rebellion were said to have so many dead that “over a five square mile area, you could not set foot on ground.”
It is little studied in the US, both because it ran concurrently with the US Civil War, but also because American missionaries were very indirectly responsible for inspiring the charismatic madman, who fancied himself the “younger brother of Jesus” after reading a missionary pamphlet.
It has been proposed that, for the first time, India and China might be compelled into a “demographic war”, a World War One-type battlefield whose primary purpose is to kill off excess men, armed with only rifles, grenades and artillery, and fighting over desolate, high mountain ranges in extremely cold weather.
The professional armies of both nations would remain in reserve, just in case an unanticipated breakthrough happened. Otherwise, the intent would be bloody stalemate. A tacit agreement between the two sides would be that the war would remain conventional, and that no important territorial changes would occur.
Fed only a ball of rice a day, and armed only with a rifle and artillery, which is responsible for most battlefield casualties, the war would continue until enough excess males had been eliminated on both sides.
Yes, there may be armies of single men fighting similar armies from neighboring or nearby countries. It just eliminates them faster, that's all. Armies are not a threat to a nation that has sophisticated weaponry, they are only a threat to a similarly underpowered country within close proximity.