The late 1960s brought an insurgence of the "baby boomers", a large populous of children born from 1945-1950. Now in their late teens and 20s, this generation sees the flaws and dangers in the Vietnam War, nuclear war, and the restraints of civil inequity. As a result, the media followed the counterculture. Movies like Bonnie & Clyde (1967) and Easy Rider (1969) were successful in emulating the counterculture's dissatisfaction with society. Rock n' Roll and soul were laced with activist messages. Theatre especially dedicated music and straight plays to the rebellion, and maintains its popularity even today. And of course, the comic industry disregarded the code with a revamp of their safer characters, and underground comics emerged as not only a mirror of the times, but as a grotesque satire.
Both DC and Marvel addressed the social and political issues of the young people. Marvel already had a head-start with their atomically themed characters (The Fantastic Four, Hulk, Spider-Man, X-Men, etc.), but in the late 60s that was taken to a new extreme. Characters like the Silver Surfer were created, characters that were alien to Earth but realized its aesthetic beauty, only to realize that the undesirable parts were closer than initially thought. In The Amazing Spider-Man #96-98 was a three-part arc concerning Harry Osborne (his best friend and roommate) and his addiction with pills. Other subjects like racism and politics came into view as well. The comic book industry stretched the rules without concern of what the code had to say, and came out successful. Characters like Captain America seemed to hit a mid-life crisis with America being so torn. Although his purpose was to protect patriotic values, he reached a time to decide which values were the right ones. Viet with his new partner Falcon, they set out to fight social and political injustice, taking their battle all the way to the White House with plenty of references to the "establishment" and Nixon administration.
DC's comics took another approach. A type of anarchist himself, Batman sympathized with the cause of the counterculture, but would not condone their violence. Both he and Robin observed that either group uses action rather than words, a message to some protestors. In one issue of The Green Lantern, the Green Arrow intervenes Lantern's meeting with the Guardians to remark on the condition of society. He tries to knock some sense into Green Lantern to keep his focus on the world he protects rather than the galaxy.
Civil and gender rights would be tackled into the '70s, especially with superhero teams. Already existing characters like The Silver Surfer would relate to those who were segregated, because they were as different but still wanted to be accepted. Marvel would create minority characters like Luke Cage, Black Goliath, and the international group of X-Men (who appeared in 1975). DC would not incorporate minority superheroes until the late '70s, and it would not meet popular reception. In terms of gender retaliation, In 1970 Marvel would present the Lady Liberators, a short-lived group of female heroes that wanted to exterminate the "male, chauvinist pigs" around the planet.
Overall, comics gained a huge audience in the 1960s due to its renewed relevance. Even the New York Times Magazine commented on how comics did and would mature to represent further generations, and in the 60s could deal with heavy issues like drug use, the Vietnam War, civil rights, feminism, and environmentalism.