As a result of growing social liberalism in the 1900s and 2000s, members of the LGBT+ community have gained new rights and social recognition in their pursuit of equality. 

Women's rights movements in the 20th century challenged the views that women are second-class citizens not deserving of rights, forging a path that would bring women to equal status as their male counterparts. 

Interracial laws and the impact they may have had on the amount of interracial marriages that occurred during the 20th century

Despite the amount of change the US has achieved in legal terms toward ethnic/racial equality, there are still many obstacles for interracial couples, especially those who have a foreign partner.

Society is becoming more and more accepting of cohabitation as an alternative relationship arrangement to marriage.

Love and companionship are the biggest reasons that people cohabit and marry. The notion that marriage is the result of romantic love has sustained through the centuries.

Cohabitation has been fighting an uphill battle when it comes to legal rights. When the time comes to part ways, cohabiting couples do not enjoy nearly the same amount of property distribution, financial support, and childcare rights as married couples.

There has been a change in the societal views of marriage over time. However, each researched topic has changed the institution of marriage in different ways.