Marrying a wife who is in 8th grade is generally considered inappropriate and illegal in the United States. The legal age of marriage varies by state, but it is typically set at 18. However, some states allow marriage at a younger age with parental consent or judicial approval. The age of 8th graders is generally between 13 and 14 years old, which is significantly below the legal age of marriage in most states.

The reasons for this are multifaceted. Firstly, children at this age are still developing physically, emotionally, and mentally. They lack the maturity and understanding necessary to enter into a legally binding contract such as marriage. Secondly, there are significant risks associated with child marriage, including increased rates of domestic violence, sexual abuse, and poor educational outcomes. According to a report by the United Nations Children's Fund (UNICEF), girls married before the age of 18 are more likely to experience domestic violence, and child brides are also more likely to die in childbirth.

Data from the National Center for Health Statistics (NCHS) shows that in 2020, the median age at first marriage for women in the United States was 27.4 years. This indicates that the majority of individuals are not married until they are well into adulthood. Additionally, the NCHS reports that the percentage of women who were married before the age of 18 decreased from 10.5% in 1970 to 2.5% in 2020. This trend reflects a societal shift towards recognizing the importance of maturity and independence before entering into marriage.

Furthermore, child marriage is often associated with poverty and lack of education. According to the World Bank, girls who marry early are more likely to experience poverty later in life. This is due to a variety of factors, including limited access to education, reduced employment opportunities, and increased vulnerability to domestic violence. The intergenerational cycle of poverty is further perpetuated when children are married off at a young age.

In conclusion, marrying a wife who is in 8th grade is not only illegal but also unethical and harmful. The age of 8th graders is far below the legal age of marriage in the United States, and there are significant risks associated with child marriage. The societal trend towards delaying marriage until adulthood reflects a recognition of the importance of maturity and independence.