One factor may be that an increasing number of men delayed the age of marriage, which allowed women to marry later in life without them worrying about the quality of older men. Other factors include the changing nature of work, with machines replacing physical labor, thus eliminating many traditional male occupations, and the rise of the service sector in which many jobs are gender neutral. Another factor that may have contributed to the trend was the Equal Pay Act of 1963, which aimed at abolishing wage disparity based on sex. Such legislation diminished sexual discrimination and encouraged more women to enter the labor market by receiving fair remuneration to help raising families and children. At the turn of the 21st century, the labor force participation began to reverse its long period of increase. Reasons for the change include a rising share of older workers, an increase in school enrollment rates among young workers, and a decrease in female labor force participation.The labor force participation rate can decrease when the rate of growth of the population outweighs that of the employed and the unemployed together. The labor force participation rate is a key component in long-term economic growth, almost as important as productivity. A historic shift began around the end of the Great Recession as women began leaving the labor force in the United States and other developed countries.
Trinucleotide repeat disorders, also known as microsatellite expansion diseases, are a set of over 50 genetic disorders caused by trinucleotide repeat expansion, a kind of mutation in which repeats of three nucleotides (trinucleotide repeats) increase in copy numbers until they cross a threshold above which they become unstable. Depending on its location, the unstable trinucleotide repeat may cause defects in a protein encoded by a gene; change the regulation of gene expression; produce a toxic RNA, or lead to chromosome instability. In general, the larger the expansion the faster the onset of disease, and the more severe the disease becomes.Trinucleotide repeats are a subset of a larger class of unstable microsatellite repeats that occur throughout all genomes. The first trinucleotide repeat disease to be identified was fragile X syndrome, which has since been mapped to the long arm of the X chromosome. Patients carry from 230 to 4000 CGG repeats in the gene that causes fragile X syndrome, while unaffected individuals have up to 50 repeats and carriers of the disease have 60 to 230 repeats. The chromosomal instability resulting from this trinucleotide expansion presents clinically as intellectual disability, distinctive facial features, and macroorchidism in males. The second DNA-triplet repeat disease, fragile X-E syndrome, was also identified on the X chromosome, but was found to be the result of an expanded CCG repeat.