Eldest Son Syndrome Is Real—Here's What It Means for Kids and Their Parents

Are you a people-pleasing overachiever with a highly attuned ability to “read the room”? Let me guess—you were the oldest kid in your family. Eldest daughter syndrome has been gaining traction on social media with many women identifying with the term that describes the unique expectations and responsibilities that come with being the oldest daughter in the family unit. And even though I myself am not the oldest daughter, I can see how this Birth Order Theory makes sense. But with a 5-year-old son and a 2-year-old daughter at home (plus another kid on the way), I’m curious how things play out when the sibling order starts a little differently. Is there such a thing as eldest son syndrome? According to licensed marriage and family therapist Kati Morton, the answer is yes. But what does that look like exactly? And how does it differ from eldest daughter syndrome? And am I messing up my 5-year-old forever by telling him to set a good example for his little sister? Here’s what the expert has to say about it. 

Kati Morton, LMFT, is a licensed marriage and family therapist, best-selling author and highly sought-after speaker in the field of mental health. She has a master's in clinical psychology from Pepperdine University and has contributed to national publications such as the New York Times, USA Today, The Hollywood Reporter, Glamour UK, Bustle, INSIDER, HUFFPOST and more. Morton recently broke down the eight signs of “eldest daughter syndrome” in a TikTok video that has been viewed over six million times and was recently featured in a New York Times article titled, "Why Your Big Sis Resents You.” 

Whether you’re married to an oldest son or you have one at home, here’s how this particular placement in the sibling chain may play out: 

1. Early Assumption of Responsibility: “Eldest sons often take on leadership roles within the family, managing household tasks and helping with siblings from a young age. This often comes at the cost of their own childhood,” says Morton. Think: Keeping an eye on his baby brother at the playground instead of playing with his own friends.  
2. High Expectations: These can come from parents but also from the kid himself. Per Morton: “Sons tend to feel more pressure to be successful, make a lot of money, and even support the family. This can be very stressful for the eldest son.” 
3. Early Maturity: “Eldest sons tend to mature more quickly due to their responsibilities and the expectations placed upon them, often behaving more like adults than children.” Also known as parentification, one of the knock-on effects from this is that oldest sons may not get the opportunity to be kids by acting silly or being out of line. 
4. Fear of Failure: Does your oldest son freak out over a bad grade? Beat himself up when he doesn’t make the penalty shot in basketball? “They may develop a fear of failure due to the high standards set by themselves and others,” says Morton. “They can feel like their entire family depends on them to be a good role model and to make a lot of money. The stress of this pressure can make them terrified of not measuring up.” 
5. Protector of Siblings: “They may feel a strong sense of responsibility to protect their younger siblings from harm or trouble. This may even be initiated by their parents, who may expect them to talk to their younger siblings' teachers or tell off their younger brother’s schoolyard bully. They can feel like they are the ones responsible for making sure everyone is safe and okay.” 

Some of the above traits may sound similar to those of the oldest daughter. And truthfully, as the firstborn in the family, there’s a lot of overlap. But there is also a gender divide, notes Morton. And perhaps it’s no surprise that the difference comes down to physical versus mental labor. “Sons tend to feel more pressure to make money and be successful whereas eldest daughters tend to feel more responsible for the emotional labor of the family,” Morton explains. 

Imagine Thanksgiving dinner with a group of grown-up kids—the oldest son may be focused on buying the biggest turkey with all the fixings and making sure his new fancy outdoor oven is working, while the oldest daughter will be making sure cousin Jenny doesn’t sit next to uncle Ron and that her mother-in-law isn’t overwhelmed with cooking the sides. 

Again, there’s a lot of overlap here between eldest son and eldest daughter syndrome. Most notably, “the constant pressure to succeed and meet high expectations can lead to stress and anxiety,” says Morton. For daughters, this may play out with some people-pleasing behaviors or issues setting boundaries; for sons this may turn into an extreme focus on achievement and monetary success. “Since they have been under pressure to succeed since they were children, this can take over their entire lives and be the only thing they care about.”

When it comes to relationships, being the oldest son can also have an impact. There may be strained sibling relationships (“their siblings can resent them for acting like their parents and feel like they stole their childhood”) and difficulty in romantic relationships (“because they have always been in charge, they can be extra controlling with those they love or even find relationships to be too much responsibility or stressful and prefer to be alone”).  

But it’s not all bad news—eldest sons are also reliable, loyal and make great leaders. 

It’s easy to put more responsibility on your oldest kid (after all—he can do all kinds of things that his younger sibling simply can’t). But try not to expect too much from them—or give them too much responsibility. If he wants to help his younger brother learn how to scoot, that’s great. But it’s still your job to make sure that said brother is wearing his helmet and practices road safety. 

Also important is how you speak to your oldest. While it’s natural to want your oldest son to be a good role model for younger siblings, phrases like “stop doing that and set a good example for your sister instead” aren’t helpful. “Just because they are older does not ensure mastery,” Mary Ann Little, Ph.D tells us. “Children should not be asked to do things they are not yet able to succeed at. While children need to have demands placed on them and must experience the frustration that fuels mastery, unrealistic expectations interfere with the building of frustration tolerance and healthy development generally,” she advises. 

Finally, keep an eye out for signs of anxiety or stress and talk to your son about some of the challenges that come with being the oldest sibling. You can also talk about some of the benefits of being the oldest and offer some special privileges too (like watching TV when the baby is napping or having a later bedtime).