What's the difference between Jr. and II? An expectant parent's guide to legacy names

Passing down a family name is a beautiful way to honor your loved ones – it can also raise a lot of questions about the "right" way to do it. 

"My husband and I are expecting our first baby – a boy – this year," says Caroline Picard, a senior editor at BabyCenter. "We love the idea of naming him after a member of our families. My father-in-law has the suffix IV, and we were wondering if we gave our son his name if he would be V, even though it has skipped a generation. (My husband has a different first and middle name.) On the flipside, if we name him after my father, would the baby need any suffix at all?"  

If you're thinking about giving your baby a family name, here's everything you need to know about using generational suffixes.

What is a generational suffix in a name?

A generational suffix is when a person has Jr., II, III, and so on added to their name. It's used when that person shares the same name as another family member (or members) – usually a father, though sometimes it's a grandfather, uncle, or even a cousin.

This tradition is most common among men. While family names do get passed down from woman to woman, it's less common to see a generational suffix added to a girl's name.

Generational suffixes are used to help differentiate people who have the same name, and are only used when every part of the name is the same – first, middle, and last.

These former U.S. presidents are some perfect examples of how generational suffixes work:

• Joe Biden's full name is Joseph Robinette Biden, Jr. His father was Joseph Robinette Biden, Sr.
• Barack Hussein Obama II also shares the same name as his father, but his parents opted to use "II" instead of "Jr."
• Bill Clinton was born William Jefferson Blythe III – his father and grandfather were both named William Jefferson Blythe.
• George Walker Bush isn't a junior because his name isn't exactly the same as his father's (George Herbert Walker Bush).

The centuries-long tradition of passing down family names is more controversial these days than it used to be. There are plenty of discussions – and opinions – about it in the BabyCenter Community's Baby Names group:

• "My husband is not technically a junior but shares his father's first name. (Their middle names are different.) They get confused by people all the time. Mail gets mixed up, accounts constantly get mixed up, I get phone calls from various people and companies thinking they are calling my father-in-law … It's annoying – and they have different middle names. I imagine it would be worse if their names were exact," says Community member Talizora.
• "Personally, I think honor names should only be reserved for the middle name. The child will be 100% unique and therefore should get its own name. But I think the middle name is a perfect spot to honor," says MamaRoses3.
• "My son is named after his dad. I never thought I would have my child be a junior or a third in my case, but we call him something totally different. I don't mind it, and it's a special name because my son's grandpa passed away," says mamaaax3.

How do generational suffixes work?

What are the rules for naming your son junior?

Jr. and other generational suffixes are only used when the name is exactly the same: first, middle, and last. Jr. specifically is used when a son is named after his father, not another relative.

Roman numerals – II, III, IV, and so on – are used when a name is passed down through several generations. Here's a made-up family as an example:

• Matthew John Smith, Sr. (grandfather)
• Matthew John Smith, Jr. (father)
• Matthew John Smith III (son)
• Matthew John Smith IV (grandson)

Roman numerals are also used when a name is passed down within a family, but not necessarily from father to son. For example, if Matthew John Smith IV's nephew is named after him, that nephew would be Matthew John Smith V. The same goes if the name skips a generation; if the grandfather is Matthew John Smith III and the father has a different name, the grandson will be Mathew John Smith IV.

I would feel some kind of way about it if my younger sibling was the IV and I wasn't. Like I wasn't good enough to pass on the legacy?

– BabyCenter Community Member 111511

If you're giving your son the same first and last name as his father, but a different middle name, you wouldn't use a generational suffix. It's not unusual to do this and call your son Junior anyway – but as with any nickname, Jr. wouldn't be on your baby's birth certificate.

"My son's name is Cory, but because he and his dad have the same [first] name, we call him Junior when they both are around," says BabyCenter Community member Dedeaka1990.

Is there an equivalent for women?

There's no formal version of a generational suffix for women who pass down their names. It likely never caught on because women more commonly change their surnames when they get married.

So while a mother and daughter sharing the exact same name may be confusing while the daughter is growing up, the daughter often ends up changing her surname anyway, making a Jr. or other generational suffix unnecessary.

BabyCenter Community member fyrewife shares that she has a family name passed down through generations: "My mom and I had the same name growing up, and I hated it. I was always Little X."

What's the difference between II and Jr.?

Jr. typically is used when a son shares the same name as his father. II might be used if the child is named after his grandfather or another relative, like an uncle. 

If you're planning to name your son after his father, though, there's no rule stopping you from using II instead of Jr.

Does a junior have to be the firstborn son? Can a younger son be a junior?

It's unusual for a younger son to carry a generational suffix instead of the firstborn son – but it does happen.

BabyCenter Community member Fleurwaxx shares such a naming conundrum: "We're having our second baby early next year. With our first son, my husband wanted to name him IV (his name is Charles Walter III), but I didn't really want to deal with suffixes. So I joked that if the next one would still be a boy, then we'll name him IV."

Other Community members are divided on the issue. One person responds, "My thoughts are that it should have been done for the first boy if it was going to be done at all, since that's usually tradition."

But another says, "I like the tradition … You said you would for this one, so you should keep your word. [Your son] will have a link to his past ancestors through his name."

You may also want to consider what your children might think about it. Will your firstborn feel jilted if you give a younger child a family name?

In that same Community thread, another member says, "I would feel some kind of way about it if my younger sibling was the IV and I wasn't. Like I wasn't good enough to pass on the legacy? And if I was the younger sibling who got the IV, I think I would wonder why my older brother got his own name and I didn't."

Can you be a junior with a different first name?

No. The reason Jr. exists as a suffix is so people can tell the difference (on paper) between a father and son who have the exact same name.

You could, if you want, name your baby Junior and put it on your baby's birth certificate – though that would make them Junior with a capital J, not a junior.

If you have a junior, do you have to change your name to senior?

No, a father doesn't legally have to add Sr. to his name if he shares his name with his son. It's most common to add Sr. informally – though if you want to make it official, you definitely can.

But then you'd have to deal with the whole hullabaloo of legally changing your name.