In the 1980s, pediatrician Richard Ferber became famous for his prescribed method of allowing babies to cry themselves to sleep, which he outlined in the best-selling book "Solve Your Child's Sleep Problems." Ferber critics have argued, however, that "Ferberizing" is emotionally damaging to infants.

Dr. Benjamin Spock became a household name in post-World War II America with the publication of "Baby and Child Care," in which the pediatrician reassured parents that they instinctively knew more about child rearing than they probably thought.

Dr. Benjamin Spock's "Baby and Child Care" has sold like gangbusters since its initial publication in 1946. By 2000, sales of the popular parenting title had surpassed 50 million, and by its 65th anniversary in 2011, Spock's manual had been translated into 39 languages. Partially due to its staggering success, TIME magazine also named it one of the most influential non-fiction books of all time in 2011.

In April 2011, Caplan published "Selfish Reasons to Have More Kids: Why Being a Great Parent is Less Work and More Fun Than You Think," which outlined his serenity method that hinges on the theory that nature plays a more prominent role in how kids develop than parenting. And for that reason, Caplan encourages moms and dads to -- in the words of the "Serenity Prayer" -- accept the things they cannot change.

When Alicia Silverstone posted a blog video of her feeding her son Bear Blu directly from her own lips, images of the mouth-to-mouth method immediately danced across the Internet. Although Silverstone was criticized for pre-chewing the baby's food, pre-mastication -- or "kiss feeding" -- is still practiced in undeveloped areas of the world where baby food and food processors aren't available.

Proposed by journalist-turned-parenting expert Carl Honoré, slow parenting posits that children should be given ample time for free play and relaxed family bonding. His 2008 book “Under Pressure: Rescuing Our Children from the Culture of Hyper-Parenting” represented a growing backlash against over-managing and over-scheduling kids' lives with excessive extracurriculars, specialty coaches and play dates.

In 2011, Amy "Tiger Mom" Chua stoked a major parenting debate with her book "Battle Hymn of the Tiger Mother," in which she describes her extreme style of raising her two daughters, which prohibited them from attending sleepovers, participating in school plays and watching television. While critics claimed that she was emotionally damaging her kids by implementing such harsh household rules, Chua maintained that she was merely grooming the girls for success.

Attachment parenting is all about fostering child-parent bonding and close contact. Instead of putting babies to sleep in cribs, for instance, attachment parents nest their little ones in bed with them, and in lieu of strollers, attachment parents often tote around their babies in snug-fitting slings.

As "serenity method" proponent Bryan Caplan posits, behavioral genetics research on twins has found little to no correlation between various parenting styles and child's long-term health and wealth outcomes.

The Great Recession has left an increasing number of high school and college graduates with pitiful job prospects. Moreover, a Millennial trend of overparenting left many young adults heavily reliant on their parents. The combination of those forces has sent millions of young men and women, nicknamed "boomerang children," back home to live with mom and dad.