The widespread microarray technology capable of analyzing global gene expression at the level of transcription is expanding its application not only in medicine but also in studies on basic biology. This paper presents our analysis on microarray gene expression data in the CEPH Utah families focusing on the demographic characteristics such as age and sex on differential gene expression patterns. Our results show that the differential gene expression pattern between age groups is dominated by down-regulated transcriptional activities in the old subjects. Functional analysis on age-regulated genes identifies cell-cell signaling as an important functional category implicated in human aging. Sex-dependent gene expression is characterized by genes that may escape X-inactivation and, most interestingly, such a pattern is not affected by the aging process. Analysis on sibship correlation on gene expression revealed a large number of significant genes suggesting the importance of a genetic mechanism in regulating transcriptional activities. In addition, we observe an interesting pattern of sibship correlation on gene expression that increases exponentially with the mean of gene expression reflecting the enhanced genetic control over the functionally active genes.