Single males in non-regular employment have a much lower marriage rate than that of regular employees, a government survey has shown.Moreover, the birth rate is lower among female non-regular workers than their regularly-employed peers, according to the survey.The results of the survey conducted by the Health, Labor and Welfare Ministry suggest that the low marriage and birth rates are due partly to Japan's insecure job market."Salaries for irregular employees are lower, and it's harder for irregular workers to take child-care leave. These factors apparently discourage them from marrying and having children," a ministry official said. The ministry survey, the sixth of its kind, was carried out in November 2007 on roughly 16,000 men and women, who were aged 20 to 34 as of October 2002 when the first survey was held.According to the results, only 12 percent of single males who worked as irregular or temporary workers got married over the five-year period from October 2002, compared to 24 percent of permanent employees. The rate for unemployed men was 9 percent.By annual income range, only 8 percent of men who earned less than 1 million yen got married, while 21 percent of those who made 4 to 5 million yen got married, the survey showed.As for women, there were no significant differences in the marriage rates between regular or irregular employees. However, the proportion of married women who had children between 2002 and 2007 was only 22 percent for non-regular workers, compared to 43 percent for permanent employees and 48 percent for unemployed women.The rate of women who returned to work after birth was 67 percent for regular workers and a much lower 23 percent for irregular workers, according to the survey.