When DC decided to reboot their universe in 2011 with their New 52 initiative, they wanted to de-age many of their main characters in order to keep them young and spry. Thus at the opening of Justice League #1, the superheroes had only been around for a total of five years. This wouldnt have been a problem if DC actually did a proper reboot and started from square one; however, they wanted to keep some of the more popular elements of their previous universe specifically the Batman and Green Lantern franchises. The five-year timeline was particularly problematic for Batman due to the number of Robins hes trained over the years. This meant that DC had to scramble to find a way to explain this, as the time line didnt make sense. Apparently, while Dick and Jason where actual Robins, Tim Drake was never called Robin but rather Red Robin. Fine. Whatever. (The timeline still doesnt make sense). Things got a bit more creative when it came to Damian, the 10-year-old son of Batman and Talia al Ghul who became Robin only a few years before The New 52 began. Grant Morrison addressed this issue in the second volume of Batman Incorporated, where it was retconed that Damian was bio-engineered from Bruce and Talias DNA. All of these retcons were un-necessary had DC not rushed their reboot and took the time to plan things out.