Women are iconic in all walks of life, but it’s hard to argue that cool sisters might just be the most iconic of all. If you have a cool sister, you’ve likely gone through phases of wanting to be like her. Maybe you’ve even stolen her clothes once or twice, or unsuccessfully attempted to infiltrate her friend group. But what about the effect that cool sisters have on their brothers — is it possible that sibling dynamic is even more powerful?
In mid-March 2024, TikTok user @Geminidreamgirl333 suggested exactly. In her video, she talked about how all the cool guys she knows are cool because — wait for it — they have an even cooler sister. “It’s important to recognize that correlation,” she said in the TikTok. “They’re cool because of their sister.”
Honestly, it seems like she’s kind of on to something here. The majority of the 4,000-plus comments under her video, which has 4.1 million views as of March 29, overwhelmingly agreed with her. Even Finneas O’Connell, the Grammy-winning record producer and brother to Billie Eilish, commented that her theory is “very real.” (Of course, maybe that one’s a given, considering his sister is one of the most famous “cool girls” in the world — but still!)
In a stitch of the original video, another TikTok user, Joe Frat, dubbed this theory the “cool sister effect.” He shared how these women, including his own sister, keep their brothers in check by being brutally honest. As he explained in the video, “it’s a system of checks and balances,” in that the sisters tell it like it is when they don’t like a particular haircut or outfit their brother has. Although the criticism can bruise the ego a bit, apparently at least some of these men actually do adjust their looks or behavior based on what their sisters tell them to do. This, according to the video, causes these guys to actually be cooler — especially, it seems, in the eyes of other girls and women. According to this TikTok, if a man gets complimented after being criticized by their cooler sister, they just got “sistered.”
In response to this video, influencer Alissa Violet commented that she is one of those cool sisters, and Joey Graziadei, star of Season 28 of The Bachelor, commented that he could confirm the cool sister effect is real. When the celebs get in on a theory, you know it holds some weight.
So, there you have it: Cool sisters apparently make their brothers cooler, whether they notice it or not. They ensure their brothers look good and dress well, but keep them humble with a healthy dose of sisterly snark.