The one-child policy has also stirred discussions among Japanese and South Korean media as tensions ratchet up over territorial disputes surrounding the Diaoyu Islands, or Senkakus as they are called in Japan. A report in the Korea Times in December proclaimed “the PLA would be defeated by Japan’s Self-Defence Forces if the Diaoyu conflict [happened] because most Chinese soldiers are spoiled little emperors and queens”.

Professor Liu Mingfu from the PLA National Defence University told Nanfang Weekly that at least 70 per cent of PLA soldiers were from one-child families, and the figure rises to 80 per cent among combat troops.

In an open report to the central government in 2012, Liu stressed that sending a Chinese family’s only son to battle had been taboo since ancient times. He pointed to the example of the US  military’s sole survivor policy, introduced after the five brothers of the Sullivan family were killed during the sinking of the cruiser USS Juneau in the Pacific during the second world war.

In Japan, military leaders have the responsibility to prevent sending eldest sons on high-risk missions, Liu added.

Antony Wong Dong  , a Macau-based military expert, said many mainland military officials and observers have voiced concerns about the impact of the one-child policy to China’s long-term  security since 1993.

“Under China’s strict military rules, deserters are shot on the spot, and even if only-child soldiers  are not afraid to fight, who will be responsible for their families if they die in battle or are severely wounded?” he said.

Sun, the Dalian soldier, said recruits usually need two years to adjust to life within a unit through tough routine training and psychological counselling.

Liu said the army had devised special training for “spoiled boys and girls” to strengthen its fighting capability in the past years, but the high rate of single children in the PLA was still a “strategic fear” for China’s long-term military development. The army has faced a serious lack of qualified manpower for at least a decade.

President Xi Jinping, who is also chairman of the Central Military Commission, told the third plenum of senior Communist Party leaders in November to relax the 30-year-long one-child policy by allowing couples in which one parent was a single child to have a second child.

However, Professor Ni Lexiong, a Shanghai-based military expert, said scrapping the birth control policy would not help the PLA solve its manpower issues for another two decades.

“The army needs to wait at least 20 years until all the second babies are young adults,” he said. “That means we can’t go to war without serious concerns.”

However, Scott Harold, a political scientist with the Rand Corporation think tank, didn’t think the one-child policy would lead to the failure of the PLA.

“Whether singletons or children from multi-child families, in wartime, a soldier fights to stay alive, and to keep his fellow soldiers alive – whether one has siblings or not,” he said, adding that the PLA’s hardware, logistics and command had steadily improved in the three decades since its border war with Vietnam in 1979.

“With some of the PLA’s most powerful abilities concerned with cyber attacks, anti-satellite warfare,  long-range precision conventional strikes and submarine warfare capabilities,  it is unclear to me how the fact that someone operating those systems is a single child would make much of a difference,” Harold said.

“I suspect corruption in the force plays a much greater role in sapping morale than the supposed concerns of a single-child-heavy force.”