This Kid Is Ours (1973)

Immediately following the events in Adiós, Cigüeña, Adiós (1971), Arturo, Paloma, and their friends now face a struggle with their parents and various other authorities over what is to be done with their new addition to the gang. Arturo's father just wants the whole matter to go away, Paloma's father prefers to dump the baby at a foundlings' home run by nuns, and the nuns don't care where the infant originated or what his parents want for him. All other options exhausted, the gang ultimately has no choice but to make a daring raid on the foundlings' home to get their child back, because, as they've repeatedly pointed out... "The child is ours!"