These dramas are near opposites which share the same catalysis of the government creating a program to increase Japanese birth rates.
Otona Koukou doesn't take this premise seriously at all and instead uses it as a premise for comedy amongst a fun cast of characters. Kekkon Aite takes this concept as seriously as it can to make a political statement about the social consequences this program would have on various Japanese minorities.
Both share the similar traits of having well-written and respected queer side characters who are given lots of plot relevance. Both also ultimately end up sharing the critique of the failures of this program in creating a long-lasting healthy relationship.
Otona Koukou doesn't take this premise seriously at all and instead uses it as a premise for comedy amongst a fun cast of characters. Kekkon Aite takes this concept as seriously as it can to make a political statement about the social consequences this program would have on various Japanese minorities.
Both share the similar traits of having well-written and respected queer side characters who are given lots of plot relevance. Both also ultimately end up sharing the critique of the failures of this program in creating a long-lasting healthy relationship.