In a Shenzhen factory, workers sit along a production line, packing expensive headphones that in just days will land in the hands of consumers across the world.
Young Chinese women have long churned out products for western shoppers. But the scene on the line points to a big change – roughly half the workers are men.
Liam Casey, chief executive of PCH International, which owns the plant, says factories in south China are turning to men as they cannot hire enough women.
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"When I would go to the factories before, back in the 1990s and right through the early 2000s, it was always women on the production lines," says Mr Casey. "Now it is a lot of men . . . It is a complete change."
Factories in the Pearl River Delta, the manufacturing area in Guangdong that has propelled China's export-driven economic rise, have long preferred to hire women. But they are now employing more men because of a tightening labor market that is also pushing up wages and forcing some companies to relocate inland or overseas.
In her book Factory Girls, Leslie Chang estimated that 70 per cent of the workers in the large manufacturing city of Dongguan were women. Although statistics are hard to find, many factories across Guangdong say they now hire an equal number of men and women.
In 2006, PCH had 14 male factory workers for every 100 women, but now the ratio is roughly 50-50. Melissa Tsui, a manager at Eagle, a company with 4,000 workers that makes car audio systems and Japanese pachinko arcade machines, says it too employs as many male as female factory workers.
"Years ago, when we had a choice . . . we preferred girls rather than boys. But at the moment we have to look for someone, whether they are boys or girls," says Ms Tsui.
The changing labor landscape is creating new personnel challenges. Many men who call an employee hotline at PCH want company-run date nights to help them find girlfriends. Meanwhile, at Eagle, the Eagle Times newspaper tells workers about basketball games – a favorite pastime of the men.
"There has been a noticeable shift away from the 'factory girl' model of the early 2000s when there was still an ample supply of young women from the countryside," says Geoffrey Crothall of China Labor Bulletin. "Those factory owners recruited young women specifically because they thought they would be hard working, obedient and relatively docile."
There are many reasons for the change. Zhai Yujian, a labor expert at Shenzhen University, says a nationwide shortage of young workers due to demographic changes has been compounded by Chinese companies moving inland, where they can pay cheaper wages. Women in the poorer provinces now have less reason to leave home – and often their children – for Guangdong.
Anita Chan, a Chinese labor expert at Australian National University, says women are less willing to "go out" – referring to the Chinese expression to describe migrant workers leaving home. "If you can find work near where you live, then it is much easier than cross-provincial migration," she says.
Previous generations of Chinese women were willing to work in factories that would provide at least a stable income, but their daughters often have different ambitions.
"Girls born in the 1990s . . . want to experience different lifestyles, work different jobs and enrich their life," says Michael Liu, a manager at Maisto Industries, a company with 2,200 workers in Dongguan that makes toy cars.
He adds that women are taking advantage of the growing number of service jobs in China, and that many would now rather work in a McDonald's than in a factory.
Companies are responding in different ways to the tighter labor market. Ms Zhai says factories that are desperate to avoid hiring men are hiring women with lower education levels and higher ages. At Maisto Industries, the percentage of female workers over the age of 30 has risen from 19 per cent to 42 per cent over the past five years.
Some companies are also sending recruiters to other provinces for the first time. Stanley Lau, managing director at Renley Watch Manufacturing, which has factories in Guangdong and Switzerland, says other companies are being forced to relocate to lower-wage countries such as Vietnam and Indonesia.
Mr Lau says Chinese factories would like to raise wages at home to attract more workers, but that they cannot afford to raise costs. "Customers squeeze the price like hell. On the one hand, they ask for better conditions [in factories], on the other hand, they squeeze the price like hell."
China's one-child policy has also contributed to the tighter female labor force. More girl than boy fetuses are aborted in China because of the traditional preference for boys, which has skewed the country's gender balance.
Amanda Wang, another Eagle manager, says companies face a new reality: "There are too many boys now in China."