Teenagers in a joint family where a new adult has entered the scene are in for more problems than a child who is normalized to a new authority figure at an early age. However, there is a misconception that states such teenagers are at a disadvantage, and I contend that it is false.
Generalization is impossible in this case
It is possible to create some very good generalizations that hold up in most occasions. For example, if you are a woman then you are likely to be attracted to a man. This is a generalization but it is one that stands up most of the time. In the case of teens having trouble with a new step parent, the problem is too complex for a suitable generalization.
There are too many in ingredients in the tub to accurately figure out what is going to go right or wrong. Now, that does not mean you cannot sometimes tell. For example, if the mother cheats and takes a new lover, then the teen is likely to resent her if he or she has to live with the mother. You can usually tell that in that situation there are going to be problems. But, in many cases there are just too many variables such as how the new step parent may be a great person, or how the absent parent may push the teen closer to his or her still-present parent and his or her lover.
Seeing one parent in love again is healthy
An unhealthy relationship has a very bad effect on the teen. To see one or both of the parents happy again is usually enough to have a teen support a new relationship and accept a new authority figure.
We are pack animals and are built for this stuff
It is not as if it is against our nature to accept new people in to our group. We are not hamsters; we are pack animals and easily accept new people into our groups if the leader says it is okay. The leader or authority figure in most families is the parent, which is why a new step parent is not predetermined to have a negative effect on the teen.
A bad dad is worse than no dad
This is true of mothers, but in western society it tends to be the father that is in the wrong. Sadly, this is why fathers have such a hard time getting custody of their kids–it’s because other fathers have spoilt it for them. Nevertheless, a poor parent who is replaced by no parent is still a good thing, so even replacing that poor parent with a not-so-poor parent figure is not a bad thing.
There are just too many arguments suggesting that the insertion of new step parent will not have a predictable effect (be it good or bad). There is just the fact that the situation is too complex and there are too many variables to say that a teen will have problems if a new step parent enters the scene.