Should You Combine Bio Kids & Adopted Kids in Same Family

Dawn Davenport


When most people think of an adoptive family, they usually think of families where all the children are adopted. In fact, however, many families in the US have both adopted and biological kids. I suspect these families are on the rise. Should you combine bio kids and adopted kids in the same family?

The National Survey of Family Growth found that “an equal percentages of women who have and who have not had a birth have adopted children” and that “four times as many men who have fathered children have adopted children compared with women who have given birth.” While the language is a bit convoluted as you would expect from government bureaucracy, suffice it to say, that is a lot of families that have combined bio and adopted kids.

Reasons Families Combine Adopted and Non-Adopted Kids

I’ve seen no research on why families have both adopted and biological kids, but from what we see in our audience and online community, the following reasons are the most common:

  • unexplained secondary infertility,
  • wanting to have children in a second marriage at an older age, and
  • the desire to adopt even though they have not experienced infertility.
  • A little-discussed reason, but one that is growing, is families going back into fertility treatment after adopting, and many of them are successful.

Do Parents Favor Their Bio Kids Over Adopted Kids

Scientists have speculated that evolution would logically predict that parents would favor their biologically related children over their adopted kids. This theory, known as the Kin Selection Theory, further predicts that parents should also have less favorable perceptions of the intellect, personality, and other behavioral traits of their adopted kids, compared with their biological children.


Should families combine biological and adopted children

In general, the study found that that parents did not favor their biological children over their adopted children.


Recent research sheds light on this evolution theory of how parents of both adopted and biological kids view their children. Researchers studied 135 virtual twin pairs—similar aged unrelated siblings raised together. (Check out our resources on Virtual Twins, also known as Artificial Twins.) Of the virtual twin pairs, 41 were adopted/biological pairs and 94 were adopted/adopted pairs. The average age of the children in this study was 6 years.

The children’s IQ was tested and the parents were asked to fill out an Adjective Checklist and a Child Behavior Checklist for both children in the virtual twin pairs. Biological children scored higher on IQ tests than did adopted children, which is consistent with prior research.

In general, the study found that that parents did not favor their biological children over their adopted children. 

“Although parents rated their adoptive children higher in negative traits and behaviors like arrogance and stealing, they scored both adopted and biological children similarly when it came to positive traits like conscientiousness and persistence.”

Keep in mind that the number of adopted/biological virtual twin pairs was small and the children studied were young, but the findings are still interesting.

Creating a Family Resources on Favoritism in Parenting:

Resources to Help Blended Families

Creating a Family, the national adoption & foster care education and support organization, has many additional resources to help families that have both biological and adopted kids. Check out a few of these:

Do you have both kids by birth and by adoption? What are your thoughts – do you think you favor your bio or your adopted kids?

Originally published in 2015; Updated in 2019
Image credit: emifaulk, Gerry Balding

22/04/2019 | by Dawn Davenport | Categories: Adoption, Adoption Blog, Blog | 21 Comments

21 Responses to Should You Combine Bio Kids & Adopted Kids in Same Family

  1. Avatar anon2 says:

    This is to reach out to Anon who posted above. Although it was 4 years ago, I hope you see this comment. I feel exactly how you feel. ((Hugs)) It is an awful feeling. I too have had therapy and it helped for a while. My therapist said “it is what it is” and it helped for a while to repeat this. I have been begging God to change my heart towards my adopted child.

    I also jump back and forth between wishing I had only all adopted children or all bio children so I would have never known the difference I now know feel between them.

    • Tracy Whitney Tracy Whitney says:

      Thank you so much, anon2, for reaching out this way and sharing your experience and encouragement. Even if the original Anon never sees this, I’m certain your kind words and hope extended will resonate with someone reading now. It’s always helpful to know you aren’t alone in this journey!

  2. Avatar Jeiel says:

    Good day! I am a student and i am planning to do a research/thesis about HOW PARENTS TREAT THEIR BIOLOGICAL AND ADOPTED CHILD. This includes the communication strategies that parents do in order to reach out to their biological child especially to their adopted child. Do you have any suggestions WHY do i have to do a research paper about this topic? I hope you can help me. Thank you and God bless!

    • Dawn Davenport Dawn Davenport says:

      jeiel, we have lots of resources on this topic at Adoption A-Z Resource Guide ( ) (under combining kids). Hope this helps.

    • Avatar kathy Gerard says:

      I am the youngest biological child. My two older siblings were adopted. I was totally neglected due to overcompensation of their of adoption. I have deep anger and resentment from this. When I try to talk about it with my parents they remind of how they were abandoned. I have no relationship with my siblings due to this.

      • Tracy Whitney Tracy Whitney says:

        I’m so sorry, Kathy. That sounds very painful and damaging. But it’s good to hear a perspective like this one, even if it’s hard to hear. As a parent to both bio and adopted kids, I find myself walking a line of awareness in my attentions and my care that I never noticed before. It’s important to me that I parent each kid as they need me to do, and not get caught in overcompensating or trying to “make up” the past. I try to be mindful of them nurturing relationship with each other as well, as that is so important to our family culture.

      • Avatar Kelly says:


        I can totally relate. I found your post specifically looking to see if there are others out there in this position. In my family, the two oldest, which I am one of, are the bio children, and the two youngest are adopted. Neglect is an understatement. If myself and my bio sibling ceased to exist tomorrow, I doubt our parents would even notice, or care. I share your anger, resentment, and pain. It’s a horrible situation.

        • Tracy Whitney Tracy Whitney says:

          I’m sorry, Kelly, that you feel so invisible. I agree, it’s horrible. I hope you find a path to peace and freedom from that anger and pain. Thank you for sharing your experience.

  3. Avatar Aaron says:

    We have one of each. I feel the same about both – they are both our children. If anything, I think that adopting allowed us to experience parenting in a fresh and exciting new light. Whereas, I hear parents having their second biological kind of shrugging it off as old business.

    • Dawn Davenport Dawn Davenport says:

      I am a mom of 4 kids by birth and adoption, and I have always felt very lucky to have experienced both birth and adoption.

  4. Avatar Hanna says:

    I have two bio and two adopted. Our reason for adopting is simply that we felt passionately called to adopt. I love all four dearly, they are each my favorites at times, and I want to put each of them back on the shelf at times. Our adopted son with FASD is by far the hardest to love and sadly the what if thought does cross my mind at times but then I remember how blessed we are to be chosen to raise and provide for these beautiful human beings. Life is not meant to be easy and certainly raising kids, whether adopted or biological, is by no means easy. They are my kids just the same. When faced with challenging behavior I do think it would be easier if we only had two or three. I consider being a mother an honor (as well as my cross to bare). Love, frustration, immense pride, anger, exaustion….they are all part of the process of parenting whether adopted or biological.

    • Dawn Davenport Dawn Davenport says:

      Oh Hanna, I was smiling and applauding with appreciation as I read your comment. As the mom of 4 by birth and adoption, I wholeheartedly agree with the following: [ I love all four dearly, they are each my favorites at times, and I want to put each of them back on the shelf at times. ]

  5. Avatar Kristie Radford says:

    We adopted our first two as newborns and later became pregnant with our third. I have learned, from my experience, that true love really has nothing to do with DNA. I’d give my life in a heartbeat for any of them. Can’t love them more than that!

  6. Avatar Sara says:

    Were the adopted children international, from foster care or domestic. It can make a huge difference in both behaviors and their perception.

    • Dawn Davenport Dawn Davenport says:

      Sara, how do you think the type of adoption might affect the parent’s behavior or perception?

      • Avatar Sara says:

        Not the parent’s behaviors so much as the kids. Are they coming from understaffed orphanages where they were competing for limited attention and resources? Are they coming out of the foster system, witnessing abuse and/or being neglected in their family of origin then having been bounced from family to family and feeling rejected at every turn? And then there’s the training the parents receive ‘Your child has been traumatized’, ‘your child can (implied to mean *will*) have difficult, maladapted behavior as response to their environment’. It’s like the parents are set up to *expect* adopted children to be different (more difficult) then bio children. Even domestic infant adoption can be potentially fraught if the primal wound theory is subscribed to. Tell a parent their child is likely to be damaged and they will tend towards interpreting any behavior as maladaptive.

  7. Avatar Kristie Radford says:

    Done both. No difference. Period.

  8. Avatar anon says:

    I do favor my bio child over adoptive, and the research you cited does show some divergence in how parents perceive their adoptive children. My adoptive child is simply harder to parent. If I had to do it again, I’m not sure I’d adopt.

    • Dawn Davenport Dawn Davenport says:

      anon, that’s a hard place to be. If you haven’t sought family therapy, please give it a try.

      • Avatar anon says:

        I’ve sought therapy on several occasions, but the hard truth is that my bio kid is my favorite, and I don’t know what amount of therapy will change what my heart feels. I often wonder if the contrast with how I feel about my kids wouldn’t be so stark if I gave birth to or adopted them both. Thanks for posting this article, I think it’s a very important topic, although I think I’m not in much company based on the Facebook comments.

        • Dawn Davenport Dawn Davenport says:

          anon, I agree that it’s an important topic. I sincerely hope, however, that you are not correct that there is nothing you can to go change how you feel. We humans can and do change. Have you reached out to your adoption agency to seek help?

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