Ore to 5-nin no Yomesan ga Love Love nano wa, Mirai kara Kita Akachan no Okage ni Chigainai!?  

俺と5人の嫁さんがラブラブなのは、未来からきた赤ちゃんのおかげに違いない!?

The main character was leading an ordinary school existence until suddenly, there was a baby and thunder. Although he found it hard to believe, it turned out that the child was his own daughter from the future. As a result of this unexpected event, a 'baby club' was established at school with the help of classmates, kouhais, and teachers. This resolved one issue, but then the protagonist inherited a large enterprise. Due to measures aimed at combating the declining birthrate among the wealthy, it is customary for men to have multiple wives. As such, he proposed to all members of the baby club.