English equivalent to the Swedish idiom "A dear child has many names"
Solution 1:
This strikes me as conveying a similar sentiment:
Victory has a thousand fathers, but defeat is an orphan. Former U.S. President John F. Kennedy
While Kennedy popularized this saying, there is some question concerning priority. For example, this post attributes the saying to Count Galeazzo Ciano, Italian dictator Benito Mussolini's foreign minister and son-in-law, who supposedly recorded it in his diary. Either way, it captures the sentiment that "A dear child has many names." By analogy, "a dear child" corresponds to "a victory" and "many names" corresponds to "many fathers". By the same token, an "unloved child" corresponds to "an orphan", who has no fathers and no names.