The purpose of this thesis is to investigate the link between advanced paternal ages (APA) (i.e., APA ≥ 35 years and APA ≥ 50 years) and genetic diseases and congenital anomalies. Currently, the relationship between both advanced paternal ages and genetic diseases and congenital anomalies remains unclear. However, there is room for improvement to systematically investigate the relationship between specific congenital anomalies in newborns and advanced paternal ages. More recently, the link between advanced paternal age (as opposed to existing studies analyzing advanced maternal age alone) and genetic diseases has been recognized by researchers, epidemiologists, and various health experts. Thus, this study serves to examine the effect of advanced paternal ages on the likelihood of birth defects using a new dataset intended to discover those relationships. I create three different datasets and utilize 12 statistical models to analyze the relationship between advanced paternal ages (APA ≥ 35 years and APA ≥ 50 years) (while including advanced maternal age or AMA [AMA ≥ 35 years]) and genetic diseases and congenital anomalies. I focus on Down syndrome, cleft lip with or without cleft palate, and meningocele/spina bifida and explore the relationship between both advanced parental ages. I explore whether (a) the advanced paternal ages and (b) the advanced maternal age increase the likelihood of newborn reproductive defects: (a) Down syndrome, (b) cleft lip with or without cleft palate, and (c) meningocele/spina bifida. This study includes all U.S. births between 2016 and 2019 using the CDC Natality Registry[1] database (2020). I perform the analyses using logistic regression models (to estimate odds ratios) that provide explanations of the relationship between each birth defect and advanced paternal ages. Analysis results suggest that advanced paternal ages (APA ≥ 35 years and APA ≥ 50 years) are positively associated with Down syndrome, whereas advanced paternal age (APA ≥ 35 years) is negatively associated with cleft lip with or without cleft palate. The results from the advanced paternal ages models do not suggest any causal relationship/effect on spina bifida. The results of this study are expected to offer some insight of the following reproductive defects: (a) Down syndrome, (b) cleft lip with or without cleft palate, and (c) meningocele/spina bifida. [1] Collection of data for all variables used in this research are obtained with full permission from: United States Department of Health and Human Services (US DHHS), Centers for Disease Control and Prevention" "(CDC), National Center for Health Statistics (NCHS), Division of Vital Statistics, Natality public-use data 2016-2019, on CDC" WONDER Online Database, October 2020. Accessed at http://wonder.cdc.gov/natality-expanded-current.html on Jun 6, 2021, 1:24:47 PM;" United States Department of Health and Human Services (US DHHS), Centers for Disease Control and Prevention" "(CDC), National Center for Health Statistics (NCHS), Division of Vital Statistics, Natality public-use data 2016-2019, on CDC" "WONDER Online Database, October 2020. Accessed at http://wonder.cdc.gov/natality-expanded-current.html on Jun 6, 2021, 1:29:36 PM;" And United States Department of Health and Human Services (US DHHS), Centers for Disease Control and Prevention""(CDC), National Center for Health Statistics (NCHS), Division of Vital Statistics, Natality public-use data 2016-2019, on CDC" "WONDER Online Database, October 2020. Accessed at http://wonder.cdc.gov/natality-expanded-current.html on Jun 6, 2021, 1:07:36 PM."