"My Two Dads" is my most recent obsession. It's a brilliantly designed sitcom in its straight forward approach to modern family dynamics and structures moving outside the nuclear family, especially after all the tragedy the AIDS pandemic had recently brought to the world. The whole series is a unique product of its time--one that certainly couldn't be replicated now or any other time. 
It's 1988 in New York City. Gay marriage is illegal in the majority of states, and gay representation on television is rare and often derogatory. Having a family as a gay couple is nearly impossible. A precondition to adoption in many states is marriage. On occasion, in more modern cities such as NYC, an individual in a gay relationship may adopt, but only if they manage to find someone in the system willing to place a child in the care of same-sex parents. However, in other situations, same-sex couples having children is increasingly common. Many couples began having children via insemination services, as well as those with step-children or children from a previous marriage. To make "My Two Dads" acceptable to the general television audience, these writers presented a work-around just bizarre enough to give their target audience what they want while still flying under the radar. In the pilot, Michael and Joey are both brought to court for the reading of the will of a college girlfriend they both had and fought over, leading to the breakup of their friendship. They hadn't seen each other in nearly thirteen years. Their college girlfriend, Marci, has just died and left them both equal custody of her twelve year old daughter Nicole. No one knows which man the father really is, because the DNA test was "indeterminate." The will specifies that even though they haven't been friends for years, they must parent the child together, in one household. (In the second episode, they try a joint-custody solution, but Nicole is unhappy with their arguing and wants a stable household, and Michael quickly realizes he cares more about his new family than his expensive uptown apartment).
There is something to be said about Joey and Michael's dynamic. They are polar opposites--Joey is a fun-loving artist, and Michael is a perfectionist, wealthy financial advisor. Still, they were childhood best friends. They have always known each other, they know everything about each other, and already have a well-established relationship with each other's parents and family. They had been with each other long before either of them had been with Nicole's mother.
This works perfectly for this situation, because the audience knows they already have chemistry, or they never would have been so close as children. It's far more believable that these two would parent a child together and create a happy family than if they had just been two people who happened to love the same woman, once. There is an intimacy between them that separates their situation from the average shared-custody situation.
Apart from the situation, this is a completely functional, average, heartwarming 1980s sitcom complete with the apartment tenants, the landlord right below them, and several characters in their general proximity. The first season plays in all the common sitcom tropes of the era, and it did them a huge favor, making their relationship to each other and to Nicole comfortable and easy. This is the reason that sitcoms were so impactful on American culture and the perception of people in minority groups--they made difficult subjects for the middle class population funny and easy to understand. It put these real-life situations in a setting that promotes empathy.
As the audience shifts, so do the family dynamics. Understandably, the beginning of season 1 emphasizes how straight the two of them are. In fact, the set of jokes Michael's character is introduced with is him hitting on his attorney. Similarly, Joey is the common hunk, ladies' man character. In the first several episodes, the guys establish their dating routines in relation to staying home with Nicole, and experiment going on dates and bringing dates home. They start off with a relatively common issue of single parents, where the dates find out they are parents and are no longer interested in a relationship.
However, by the end of the first season the subject matter gradually moves away from the dating life and emphasizing the family dynamic they've created. It becomes a much more relaxed environment, and the permanence of the situation begins to take hold. They become a tight-knit family to the extent that, when Nicole asks for a little brother, Michael and Joey begin to foster-parent a little boy, expanding their family. This episode deals once again with the difficulties same-sex parents face, moving from the challenges of adopting to the highs and lows of expanding the family.
One of my favorite episodes in this series follows the family as Michael's mother comes to stay for a while, her uptight and strict policies causing problems with the rhythm of the household. Joey, reasonably, is upset with her, and though they both know he can't yell at Michael's mother, he finds a loophole in firmly establishing her as his own mother-in-law. It's brought up as a simple one-liner, but it's referenced multiple times casually throughout the rest of the episode, including affectionately between the two of them at the end.
Also in this episode, they address for the first time a common issue the public had with gay couples in the late 80s and 90s, and probably even today. Having continuously stepped over parenting versus grand-parenting boundaries during her visit, Michael's mother is finally faced with her son's confrontation. He calls the problem for what it is, stating that his mother does not believe he and Joey alone can be parents and run a functional household. She tells him the infamous line about how two boys should not be playing house, because Nicole needs real parents. Michael comes back, effectively, with acknowledging that if he had met a woman and married her tomorrow, his mother would have been fine with the two of them parenting children. But he and Joey, who have known each other always, who love each other, are somehow incapable of it.
At the time, I had a theory that this episode would be a turning point in the series, propelling them onto a more direct and openly homosexual trajectory. Partially, this theory was correct. The rest of the first season establishes several things that wouldn't have been tolerated in the first several episodes. For example, Joey has his left ear pierced, and this is mentioned in multiple episodes. Additionally, politics were both directly and indirectly brought into the picture, establishing both of the guys as liberal democrats, and even bringing in Ed Koch to tell Nicole that Michael "looks a little republican." The overall premise of this episode is in itself a gem--the Judge's career is in jeopardy after an article is published questioning her abilities, based on the fact that she put a family together with two dads. The relationship of the two dads is not specified at all, which leads me to believe it wouldn't matter to the public if they were two dads in a relationship or not.
The entire first season of "My Two Dads" is groundbreaking. However, the second and third seasons don't hit quite as hard. Although of course they're wonderful, what took the charm out of it for me had to be that Nicole was entering her teen years, and she lost the innocent, sweet little girl personality she used to have. She found herself in more serious, adult situations, and the show became a little more stressful than laid back and easy. In fact, the third season I had my doubts about even watching--I didn't adapt well to all the changes.
I did end up watching season three, although to this day I can't bring myself to watch the final episode. But season three was absolutely worth watching. Overall, this show quickly became a new comfort show, and I'll probably be binging it several consecutive times!