Kosodate Play (2009)

The four housemates, Takeru Yamamoto, Ken Todoroki, Teru Himuro, and Toru Oyamada, all lead very different lives. One day, an abandoned baby is left on their doorstep with a note claiming that one of them is the father. In order to figure out who the father is, the housemates must work together to look after the child, whilst also trying to live their own separate lives.