• Proceedings of the Population Association of Korea Conference
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• 2006.12a
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• pp.59-87
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• 2006

This paper explores the effects of the 1997 economic crisis on the pattern of socioeconomic differentials in fertility. Based on analysis of data from the 2003 Korea National Fertility Survey, this study focuses on recent changes in the level of fertility according to socioeconomic status of the couple including educational level, occupation, working status, income, etc. Results reveal that the level of fertility of those with the highest education, most prestigious occupation, and employer status are higher than those of the next group in the socioeconomic hierarchy. These findings imply that the straight line inverse pattern of socioeconomic differentials in CEB yielded to a reversed J-shaped curve. However, recent differentials of fertility after the economic crisis were found to contrast with the pattern above. Decrease in fertility has been most drastic among those with a high level of fertility, and relatively slow for those with a low level of fertility. The level of recent fertility turns out to be highest among those with upper-middle socioeconomic status, followed by those with the highest socioeconomic status and those with the lowest status. Policy implications and some comments on current population policies of the Korean government are also presented in this paper.

• Journal of Families and Better Life
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• v.23 no.2 s.74
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• pp.137-148
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• 2005

This study compared one-child households' economic structures between those who determined not to have more children and those who have a birth plan. This study examined the demographic characteristics and economic variables such as income, consumption expenditures, assets. debt, and a subjective evaluation of future economic status. Especially, it compared the effects of socioeconomic variables on expenditures on a child between low-fertility and birth-planned households. From a questionnaire completed by a husband or wife of one-child households, 154 low-fertility households and 201 birth-planned households were obtained. A t-test, chi-square test, multiple regression analysis and a dummy variable interaction technique were used. The findings of this study are as follows: First, low-fertility households were older, had higher income, and had more educated, employed wives. Their marital duration was longer, and their child was older than those of birth-planned households. Second, low-fertility households had higher consumption expenditures than did birth-planned households. Especially, expenditures of apparel and shoes, health care, education, and entertainment were significantly higher for low-fertility households. Also, low-fertility households spent more than did birth-planned households on a child. However, low-fertility households had significantly more debt than did their counterparts, and their expectation level of future economic status were lower than that of birth-planned households. Third, the effects of socioeconomic variables on expenditures on a child were different between low-fertility and birth-planned households. Age, education level, husband's occupation, wife's employment status, income, net asset, and subjective evaluation of future economic status showed significant differences. Income elasticity of expenditure on a child was significantly higher for low-fertility households than their counterparts.

• The Korean Journal of Community Living Science
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• v.25 no.3
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• pp.339-347
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• 2014

This paper was examined socio-demographic characteristics influencing married women's fertility plans in Korea. Few studies have focused on fertility plans by using census data, and therefore this study employs 2010 census 2% sample data. It focuses on differential characteristics influencing not only whether women have plans for additional children but also how many additional children women plan to have. Women's age, age at marriage, employment status, number of children, and number of sons are consistently associated with their fertility plans and planned number of additional children. The educational level is positively related to plans for additional children for both men and women, and the effect weakens or disappears with an increase in the planned number of additional children. The result showing consistent positive effect of the number of sons reflects son preference in Korea. Positive effects of women's high educational attainment and employment status on fertility plans may reflect the importance of economic stability but requires further research.

• Journal of Korean Society of Forest Science
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• v.96 no.5
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• pp.528-532
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• 2007

Clonal differences in fertility (expressed as the number of female and male strobili) were determined for five consecutive years (2002-2006) in a clonal seed orchard of Chamaecyparis obtusa. Fertility varied among clones and among years with producing five-year averages of 378.8 and 871.2 for female and male strobili per ramet, respectively. Correlation between female and male strobilus production was positive over the five years and statistically significant. Based on the observed fertility variation, the effective population sizes (estimated by status numbers, $N_e$) were calculated and varied from 24.3 to 47.9 (48.6% to 95.8% of census number, N) among the five studied years. On average (pooled), the relative effective population size was 82% of the N. Variation in female fertility was higher than that in male fertility, and this variation was reflected on female and male parents' status numbers. Pooled $N_e$ estimated from the five years was higher than that from poor seed production years. From our results, it was concluded that genetic diversity collected from good flowering years would be higher than that from poor flowering years.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.6
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• pp.842-850
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• 2018

Objective: Several studies have reported the development of new molecular methods for the prognosis and diagnosis of male fertility based on biomarkers aimed at overcoming the limitations of conventional male fertility analysis tools. However, further studies are needed for the field application of these methods. Therefore, alternative methods based on existing semen analysis methods are required to improve production efficiency in the animal industry. Methods: we examined the possibility of improving litter size in various pig breeds using combined Hoechst 33258/chlortetracycline fluorescence (H33258/CTC) staining. The correlation between field fertility and capacitation status by combined H33258/CTC staining in different ejaculates spermatozoa (n = 3) from an individual boar (20 Landrace, 20 Yorkshire, and 20 Duroc) was evaluated as well as overall accuracy. Results: The acrosome reacted (AR) pattern after capacitation (%) was positively correlated with the litter size of Landrace, Yorkshire, and Duroc pigs and the overall accuracy was 75%, 75%, and 70% in Landrace, Yorkshire, and Duroc pigs, respectively. The difference (${\Delta}$) in AR pattern before and after capacitation was positively correlated with the litter size of Landrace, Yorkshire, and Duroc pigs and the overall accuracy was 80%, 65%, and 55% in Landrace, Yorkshire, and Duroc pigs, respectively. However, the difference (${\Delta}$) in capacitated (B) pattern before and after capacitation was negatively correlated with the litter size of Landrace pigs and the overall accuracy was 75%. Moreover, average litter size was significantly altered according to different combined H33258/CTC staining parameters. Conclusion: These results show that combined H33258/CTC staining may be used to predict male fertility in various breeds. However, the selection of specific efficiency combined H33258/CTC staining parameters requires further consideration. Taken together, these findings suggest that combined H33258/CTC staining may constitute an alternative method for predicting male fertility until such time as fertility-related biomarkers are further validated.

• Korea journal of population studies
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• v.31 no.3
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• pp.1-26
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• 2008

The main purpose of this paper is to explore the impacts of foreign wife status and social capital on fertility among a group of Chinese, Vietnamese and Japanese wives in Korea. Attention is focused on the argument that minority group status and immigrant social capital exerts an independent effect on fertility, apart from socioeconomic and demographic variables. It is hypothesized that the level and tempo of fertility of foreign wives reflect their social disadvantages and the adaptation process. Micro-data from two socio-demographic surveys were utilized to analyze the reproductive outcomes of foreign and native wives in Korea. Results of analyses reveal that foreign wives in Korea tend to have fewer children compared to native Korean women. It was found that a foreign wife's access to social capital significantly facilitates reproductive behavior. Those who engage themselves more in voluntary activities, have more friends in Korea, and possess better and higher-quality social networks tend to have more children. Foreign wives with a high degree of integration or assimilation to the new surroundings were also found to have more children than other foreign wives.

• Clinical and Experimental Reproductive Medicine
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• v.43 no.2
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• pp.106-111
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• 2016

Objective: To study the clinical outcomes of single frozen-thawed blastocyst transfer cycles according to the hatching status of frozen-thawed blastocysts. Methods: Frozen-thawed blastocysts were divided into three groups according to their hatching status as follows: less-than-expanded blastocyst (${\leq}EdB$), hatching blastocyst (HgB), and hatched blastocyst (HdB). The female age and infertility factors of each group were evaluated. The quality of the single frozen-thawed blastocyst was also graded as grade A, tightly packed inner cell mass (ICM) and many cells organized in the trophectoderm epithelium (TE); grade B, several and loose ICM and TE; and grade C, very few ICM and a few cells in the TE. The clinical pregnancy and implantation rate were compared between each group. The data were analyzed by either t-test or chi-square analysis. Results: There were no statistically significant differences in average female ages, infertility factors, or the distribution of blastocyst grades A, B, and C in each group. There was no significant difference in the clinical pregnancy and implantation rate of each group according to their blastocyst grade. However, there was a significant difference in the clinical pregnancy and implantation rate between each group. In the HdB group, the clinical pregnancy and implantation rate were similar regardless of the blastocyst quality. Conclusion: There was an effect on the clinical outcomes depending on whether the blastocyst hatched during single frozen-thawed blastocyst transfer. When performing single frozen-thawed blastocyst transfer, the hatching status of the frozen-thawed blastocyst may be a more important parameter for clinical outcomes than the quality of the frozen-thawed blastocyst.

• Journal of the Korean housing association
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• v.12 no.2
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• pp.161-169
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• 2001

This study has been performed to analyze association between general housing status and demographic characteristics such as family extension period, total fertility within a family, male birth rates, and birth order among the elderly in Korea. In this study, 183 subjects aged late 60s to 70s were interviewed for their childbearing history under legal marriage and current housing status such as tenure, residence(urban vs rural), and household composition. In this study , average term from the first to the last birth is 11.88 years, and total number of live births is 4.51. The average rate of male firths among live births within a family is 0.532, which is close to data of Korean statistical office in 1995. There were some association of housing status and the fertility; those living in rented units have longer family extension period and rural elderly have higher rate of male children. in addition, there is a significant impact of birth order on tenure. Majority of the first-born subjects were home owners by virtue of bequeath eligibility, and the rate of home owners was 50% higher than the second-born group. Overall in this study, it is recommended that when planning elderly living facilities, service policies be differentiated by both housing & fertility characteristics.

• Korean Journal of Soil Science and Fertilizer
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• v.12 no.1
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• pp.15-23
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• 1979

In the first paper of the series the five soil fertility factors were evaluated by means of principal component analysis and varimax method. They are interpreted as representing, 1) skeletal available phosporus status, 2) organnic matter status, 3) salt status 4) base status, and 5) free oxide status. In order to resynthesize such fragmented information for the overall soil fertility evaluation, the method of multiple regression analysis was adopted, using the five factor scores and yield data for Korean paddy soils as independent and dependent variables respectively. As test of linear models with different combinations of independent variables the results of t-test of regression coefficient were revealed that the organic matter status (FII) has no relevance to the yield of paddy and that the free oxides and salt supply has by it self only an insignificant contribution to the yield. The multiple correlation coefficient (R) revealed its multiple regression analysis was as low as 0.43. Introduction of quadratic terms to the linear model bettered the result. Thus multiple correlation coefficient (R) was increased as 0.59. Therefore, a coefficient of determination 0.35 was obtained by a quadratic model with interaction terms among the five fertility constituents. Generally we think that the fertility factor has more contribution to raise the rice yield in paddy and that the failure of yield prediction by fertility factor scores was caused by one of follows; 1) the roughness of the yield inspection, and 2) missextraction of fertility constituents. The second step in this study, assuming that the residuals by multiple regression analysis were due to factors other than soil fertility, we can now proceed to predicting the yield from the field characters with the classified fertility groups by means of Hayashi's theory of quantification No. 1. Such variables as fertility groups (FTYG), water availability (WATER), soil drainage (DRNG), climatic zone (CLIZ), surface soil's stickiness (STCKT), surface soil's dry consistence (DCNST), and surface soil's texture (FTEXT) are taken up as the explanatory variables. The quantification appears reasonable; the well to extremely well in soil drainage, very sticky of surface soil, inefficiency in water availability, coarse texture, and very hard to extremely hard dry consistence in soil are detrimental to the rice yield. The R was as high as 0.90 for the set of variables. But the given explanatory variables in this study were not quite effective in explaining rice yield. The method developed seems to be promising only if properly collected data are available. Conditions that should be satisfied in the yield inspection obtained from common cultivator for the purpose of deriving a prediction equation were put forward.

• Korean Journal of Childcare and Education
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• v.16 no.6
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• pp.19-34
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• 2020

Objective: This study investigated the effects of the firstborn's gender and temperament on the fertility intention and follow-up childbirth of parents. Methods: A total 120 firstborns and their mothers were selected from the sample of the Panel Study on Korean Children. Child temperament traits were measured by Early Childhood Behavior Questionnaire(ECBQ) and mothers stated their fertility intention in 2009 when their first child was under 2 years old. Follow-up childbirth of mothers was assessed from the data of PSKC in 2016. Results: The results indicated that there was a significant difference by gender in follow-up birth. Among aspects of temperament, fertility intention was affected by the firstborn's inhibitory control and follow-up birth was affected by the firstborn's gender and discomfort. For mothers with a boy, the firstborn's soothability affected mothers' follow-up childbirth. Conclusion/Implications: These results imply that gender and temperament of the first child are connected to mothers' fertility intention and follow-up childbirth. Extra studies are required to clarify how those factors affect mothers' parenting or psychological status. Meanwhile, the firstborn's gender and temperament should be considered when developing support programs for families with one child in order to increase follow-up birth rate.