The 'Boyfriend Twins' meme refers to the internet phenomenon where romantic partners, particularly in the LGBTQ+ community, bear a striking physical resemblance to one another. The trend gained massive traction on Tumblr and Instagram through blogs that curated photos of couples who look like they could be siblings. It taps into the psychological concept of 'assortative mating,' where individuals are subconsciously drawn to partners with similar features. The meme is widely used to humorously point out narcissistic dating habits or to challenge followers to guess if a pair is related or in a relationship. It remains a staple of social media commentary on the uncanny aesthetic synchronicity found in many modern couples.