A family structure is the composition and the association of a family membership, union and the patterning of connections among family members in their relationship. There are different family structures in the todays society. These family structures include: nuclear family which is composed of the father, mother, and the children who are either born in that family or adopted. There are extended families which are composed of the nuclear family living together with other relatives such as grand parents and cousins. Single parent family structure consist just one parent and children. Binuclear families where the two parents may be separate but they share the responsibilities on childrearing. There are also reconstituted families where the two partners may have children from prior relationships and the children from both sides are brought into the family at a later stage. The last structure is the one referred as the alternative marriages which include same sex families, communal families and foster families (Rosdahl and Kowalski 88). This discussion is inclusive of all these structure and the changes that have lead to these types of family structures.To start with, when comparing the family structures in the last and 21 century there have been a lot of similarities especially on the late 20 century. In the late 20 century, marriages have been on decline with climbing ladder on divorce cases which is also the case in this 21 century. In both there has been a change from the traditional intended family structure where mothers were staying at home bearing children and doing the household cores, the fathers were then expected to be away from home working all day to provide for the family and children being with either parents depending on the gender. In the last and 21 century we find many mothers who are working to provide for their families (Dreman 94). On the other hand there are fathers who are not employed staying at home looking after the children as their wives go to work or where the both parents alternate in carrying out of the responsibilities. Both centuries are also characterized in nuclear families.There has been a change of families from the traditional nuclear family with two biological parents to the new types of families such as single parents family and same sex family. These changes have occurred due to the following factors. The increased decay of societal morals in relation to immorality has led to children being born out of wedlock. Divorce occurrences and separation has been very high. This has in turn led to single parent family when the two parents separate (Ballantine and Roberts 343). Traditionally a woman was advised to stay in her matrimonial family even if the man became too abusive- wife battering was considered as a necessity for instance in African communities but after recognition of human rights it is considered unacceptable. This has however led to many women separating from their partners as they claim for their human rights. Due to the increased working class number in both of the centuries, many working people have opted to remain single while pursuing their carriers. Same sex families are common in both centuries but in the early 20 century they were rare.Career development has at the same time led to the increased number of many people remaining single. In the traditional set up education was not much valued, thus career development was never viewed as an issue. They claim that they do not have time to be with the family and in cases when others have gone for oversees for further studies, their partner are left single. Out of the increased death which has resulted from the increased spread of AIDs the partners to the diseased are left single. At the same time when one contracts this disease before marriage he or she mostly opts to remain single out of the stigma provided from the society.Out of the increased distrust in reference to the opposite sex, increases the same sex marriage. The broken relationships of the opposite sex have led to many opting for the same sex family as they avoid being hurt by the opposite sex. Also as a result of children being brought up in a single parented family which was not the case traditionally, they have ended up turning to the same sex for marriage. For instance when a male child is brought up by a single mother, he may feel overly in charge for his mother. When this male child gets into adolescence he may judge the female love being draining thus desiring a relationship which is said to be enjoyable and engage himself to male love by default. Loneliness where many women experience disappointment as they search for the perfect and right opposite partner thus they end up turning to women instead. Increased disorder on the gender identity especially during the adolescence period has contributed to same sex desirability leading to attraction. This mostly happens in schools where the same sex school together separate from the opposite sex. At this age they start practicing lesbianism and thus they become addicted to it where they opt for the same sex family even when they become of age.The divorced partners portray negative aspects of the other partner. For instance when a mother always gives the negativity of the ex-husband her daughter might develop disrespects to her father and men in general thus end up opting for the same sex attraction leading to marriage. As a result of conflicts in the families between the two partners, the children in those families may many times hate the kind of a family which has two opposite partners and go for the same sex families depending on psychological stress they underwent. The increased moves on legalization of same sex marriages and defending of their rights has also increased these types of families (Hull 1). When the young ladies are sexually abused by the opposite sex for instance when raped, has led to many women going for women relationships leading to marriage as their partners. This has also been the case where boys are abused by the opposite sex.