I have two stepsons as an obvious result of marrying their mother. We all get a long fine and always did. They are treated as if they were my own sons even though their father is still around.
The film shows what can happen when a single parent gets involved in a new relationship. This is an extreme example but moving on can involve huge risks as well has a permanent effect on all those involved.
Before my wife and I met, she was dating a guy who turned out to be a jerk. He didnt like her kids and vice versa! They would get into phone fights and then he would show up at the door and continue it either in the house or outside. Both boys were still rather young but didnt like him. My wife broke it off with him as a result of her boys not liking him and due to some other issues as well.
It is always a difficult situation when a single mom meets someone and moves on with her life. Ive obviously been there. Its a change for the kids as someone is going into their life and there will obviously be changes. It was also a change for me as well. How that is handled by all concerned is obviously the key.
When my wife and I met, the boys were away with their father for a month as he gets them for the entire month of July. A relationship started up and we fell in love rather quickly. I met the boys for the first time a few weeks after my wife and I met. We got along great and they took a liking to me. As the relationship moved on, it got to the point that they were always asking their mother if I was coming over.
When we decided that the next move for us was marriage, we spoke to them first and they were all for it. But by then, the oldest was asking his mother if we were going to get married. He wanted us to and was afraid of us breaking up.
It obviously worked out well. I think its safe to say that not being a drunk, drug user or drug dealer like Jake didnt hurt either! My wife and I have been married for eight years and the boys are doing fine.
My wife told me once that even though she had fallen in love with me, everything hinged on the kids. If the boys and I were unable to get along, she would not have gone forward in the relationship. At least my wife was smart enough to take her sons into consideration unlike Teri Garrs character who just wanted the sex and the drugs. Never mind the fact that the boys were suffering from her poor decisions.
My wife and I ran into that jerk she was dating. We were out food shopping with the boys and he approached her as apparently he didn't realize that I was with them. You should have seen his eyes when my wife introduced me as her fiance!

Sadly, it does embody some of the more serious issues plaguing society at the time in relation to drug abuse and domestic violence. Cocaine, as anyone who was evenly remotely aware in the 1980's will tell you was an absolute scourge. It exploded onto the scene and ran rampant throughout the culture, affecting a great many lives, regardless of class or ethnicity. This film in particular was just one of many at the time (though certainly one of the first and most noteworthy) to depict these ills in such a plain and direct manner. It's a bit cheesy and quite self-rightous, but in all fairness it was, for the most part accurate. I didn't find Terri Garr's character to be nearly as believable as Weller's, but then again, there were (and still are) such women willing turn a blind eye to almost anything for the sake of not being alone. "Firstborn" is not a film that would have worked 10 years later, let alone today, but for it's time it was quite impactful.

Agreed, it really resonated with me. I was the little brothers age and caught it several times back in the mid-80's on cable. Eventually bought it on vhs AND Laserdisc.