My kids are virtual twins. They are 4 months apart and not biologically related.

• My twins aren't technically twins, they are virtual twins instead.
• Virtual twins are kids born less than six months apart and not biologically related, but raised together.

I have twin 13-year-old boys. Sort of. One is 12, and one is 13 because we're in that pocket of the year where they're different ages. My twins aren't technically twins. They're virtual twins.

The accepted definition of virtual twins is siblings less than six months apart and not biologically related. Virtual twins sometimes go by other nicknames, such as almost twins, twiblings, or artificial twins.

My kids are four months apart. They're both adopted from China, and they are not biologically related to one another. We adopted them in 2012 and 2013 when they were 2 and 3 years old. After adopting our son Zack at age 2, we quickly decided to adopt again. The paperwork for our second adoption went very quickly and smoothly, and we were matched with a little boy, Kyle, four months older than Zack.

They have a twin-like relationship

Our social worker used the term "adopting out of birth order" and cautioned us against doing so. When people have biological children, the newest child added to the family is always the youngest, but adoption can change that up. In our case, the newly added child wasn't the baby of the family. Other than some first-month home bumps where my youngest son had to adjust to not having 100% of parental attention, we have not experienced any issues with adopting out of birth order.

Our middle son is smaller than our youngest son, and we often get the "Oh really? He's older?" when we meet new people. I find this irritating. If we meet and I tell you how old my kids are or answer your questions about which kid is older, let's try to automatically go with the belief that I'm giving you the correct answer because I'm their mom.

I've never had regular twins, but I know other twin moms, and I have much in common with them. My kids have a twin-like relationship and have the same dynamic as other twins. We went through the "dress alike" phase, which, sadly, my kids refused to have anything to do with past age 9. My kids have a strong bond and fight epic battles over stuff and space. One of the most common questions people ask us, aside from "Are they twins?" is "Do they get along?" My answer is, "Yes, except when they don't." It's all or nothing, harmony or fight club.

People ask a lot of questions

The question "Are they twins" is reasonable, but people's curiosity goes beyond that sometimes. Since our boys are Asian and my husband and I are not, the casual observer has some insight into our family dynamic that families who look the same might not understand. While I try to approach curiosity politely, I always keep in mind — and tell my kids — that just because someone is curious about our family, that doesn't oblige us to give details about our family if we don't want to.

"Are they real brothers" and even "Where did you get them?" — yes, really, people ask that — are annoying questions for us. Still, when I'm asked if they're twins, I usually just go with "No," but then the questions of "Which one's older?" or "How close in age are they?" follow, so it's hard to make polite chitchat without going into more of a family story deep dive than I want to. When my kids were younger, I frequently said, "Yes, they're twins," just to limit conversation. Now, I mostly let them answer for themselves.

Sometimes, people marvel that my kids aren't twins or at least biologically related. We get a lot of comments about how much they look alike, but they really don't. They're both Asian, but that's where the similarity ends. Some people don't see past that.

My husband and I didn't set out to have virtual twins, and we didn't plan to add to our family the way we did because we wanted to have twins. I'd never heard of virtual twins until another adoptive parent of kids close in age used that term. This is just how it worked out for us.