- With few exceptions, all able-bodied men are required to serve in the military for about two years
- Young men who decide not to serve for religious reasons usually find themselves imprisoned
- U.N. Human Rights Commission says South Korea should provide a civilian alternative
Seoul (CNN)It's a pain that Yoon Sook-kyung says only a mother could understand.
"I suffered from depression and anger. My health deteriorated," she says. "I felt my heart rip. It was that painful."
That was about a decade ago, when her eldest son, Yang Won-june, was imprisoned.
In 2010, her 24-year-old son, Yang Won-wuk, was put behind bars for more than a year. Now, her youngest son, Yang Won-suk, could be facing the same fate.
It's all because the young men refused to join the South Korean military for religious reasons.
"I feel really bad," her younger son says. "I'm the last one in my family. My parents are getting older."
With few exceptions, all able-bodied men are required to serve in the military for about two years, then report for reserve training over the next eight years.
Those who refuse face up to three years in prison -- though most end up serving about 18 months. The latest official records show about 550 people were in South Korean prisons last year for that reason.
Objection to violence
Human rights group Amnesty International says that number is significantly higher than those from other countries that have compulsory service, because there's no provision for conscientious objectors. It says the vast majority of offenders -- like the Yangs -- are Jehovah's Witnesses.
The religion prohibits any acts of violence.
"If you go to military camp," Yang Won-suk explains, "we practice many times to kill the enemy."
He says he would prefer to go prison than go against his faith; though he thinks it is unfair that he is forced to make that decision. He says he would be willing to serve in a non-violent, civilian way. But that is not currently an option in South Korea.
For young men like the Yangs, the punishment can have lingering effects after they're released from prison. With a criminal record, they often find they have limited job prospects.
The United Nations Human Rights Commission says South Korea should provide a genuine civilian alternative for conscientious objectors.
Threat from the north
A spokesperson for the military agency that oversees recruitment told CNN that is just a recommendation and not international law. In a submission to the U.N., South Korea referred to an "elevated sense of public threat" as part of the reason for its reluctance to shift its position.
University student Kim Shin-gun recently completed his service. "I think one needs to consider the unique situation of South Korea. Korea is technically at war right now," he says.
The threat from 1.1 million Korean People's Army -- North Korea's armed forces -- troops standing at the ready north of the border lies at the heart of the South Korean government's policy.
The military spokesman says it would be "premature" to change the law, and that the country needs secure military manpower.
However, there are signs attitudes may be shifting.
A judge in the southwestern city of Gwangju recently found three Jehovah's witnesses not guilty for refusing to serve because of their religious objection.
This has only happened twice before. In both of those cases, the verdicts were overturned on appeal. The prosecutors in the latest case are appealing too.