To Breed or Not to Breed: the Genetic Risks of Diabetes

My grandmother was diagnosed with type 1 diabetes as an adult, a highly unusual occurrence back in the late 1940’s. As a child, I didn’t even know she had diabetes. I did know she always carried a Chunky in her purse. You remember those wonderful hunks of milk chocolate deliciousness. She used them to treat low blood sugar, although I always thought they were for me. Along with the occasional Chunky, she also passed along diabetes. I was diagnosed with type 1 when I was ten years old.

My grandmother developed diabetes after she was done having children. In contrast, I had ample time to think about my decision. Having a child is an irreversible, life-altering decision. Philosopher Christine Overall believes that deciding to have a child is the biggest ethical decision we will ever make. Indeed.

What Are the Odds?

The genetic risk of having a child with type 1 diabetes is not entirely understood and fluctuates greatly. If the father has type 1, the child has between a 6% and 8% chance of developing diabetes. If the mother has type 1, the risk can range from 2% to 3%. If both parents have type 1 diabetes, the risk increases to 25%. There are a number of contributing factors to explain the differences. The younger the parent was when diagnosed, being Caucasian, and the child having an early history of certain childhood traumas and infections increases the odds. The older the parent was when the child was born and the longer the mother breast fed decreases the odds. There are also environmental factors to consider such as living in a cold climate and early dietary variables that can impact risk.

The genetic risk associated with type 2 diabetes is also complex. If the father has type 2, the risk factor is about 30%, slightly higher if it is the mother. If both parents have diabetes, the risk factor jumps to about 70%. There are a number of factors that impact the risk, such as obesity, sedentary lifestyles, poor dietary practices, smoking, elevated blood pressure, and a history of gestational diabetes. All increase the risk.

The Times, They Are a Changing (with thanks to Bob Dylan)

My decision to have a child was not all about odds and statistics. I also addressed the issue of my child’s quality of life living with diabetes. I was discharged from the hospital on my eleventh birthday, 1966. My physician assured me there would be a cure within five years. He missed, several times over. My, oh my, did he miss. Just the same, I’ve seen some pretty impressive advances. I have experienced glass and disposable syringes, animal and analog insulin, urine and blood testing, continuous glucose monitors, and insulin pumps. The quality of my life has improved dramatically, and I believe I am handing off a future with great possibilities. I have to believe a cure is much closer than it was in 1966, when it was a mere five years away.

I’m Only Human

I’m also aware of some psychological influences on my decision making. Like most people, mine is curiously flawed. When dealing with personal issues, I can be unrealistically optimistic. Unrealistic optimism allows us to perceive ourselves and our situations favorably. This is not all bad as it helps us to feel better about ourselves, fend off depression, and deal with all those pesky life annoyances. It can also lead us to believe we can beat the odds, particularly when the odds are not overwhelming. If I am willing to believe that I can beat the odds of maintaining a successful marriage, I can certainly beat the odds that my child might develop diabetes.

Strange Bedfellows

I tend to be a bit academic. I like research, statistics, and psychology. But I found that none of this resulted in a formula to make this decision. My wife and I decided to have a child. It was a deeply personal, intuitive, and optimistic decision. He is now 27 years old and diabetes free. But I still worry. From the very beginning I was warned by his pediatrician not to overdo it testing his blood sugar every time he peed “too often”. With each passing year I have been thankful he hasn’t had to deal with diabetes. Not that he couldn’t, just that he didn’t need to. Ultimately, our decision to have a child was not academic. There were no guarantees, one way or the other. We just had to decide what was right for us.

22 Comments
  1. It is also worth noting that the 1-2% of us with diabetes who have an autosomal dominant monogenic form (commonly referred to as “MODY”)have a 50% chance of passing along this gene and resulting diabetes to each of our children. As a physician, I diagnosed myself with diabetes in 1992 at age 33, joining my father, aunt and paternal grandfather. All of us developed diabetes as thin young adults in our 20s or early 30s. Once Type 1 had been ruled out for me, MODY became the prime suspect, and a MODY3 diagnosis was confirmed 6-7 years ago with genetic testing.

    My husband and I had already decided that having children was not for us, so my diabetes diagnosis and family history didn’t contribute to that decision. It did help to reconfirm it in some ways, however. I’m also grateful that my two siblings have not been affected by MODY, and that my four nieces and nephews are not at risk.

    For those interested in more information about MODY, I’d highly recommend an excellent 2015 review entitled “Undiagnosed MODY: Time for Action” (doi:10.1007/s11892-015-0681-7) that addresses the importance of genetic MODY diagnosis and provides a comprehensive summary of MODY epidemiology studies across diverse populations. Another superb article published in 2018, “Clinical Management of Women with MODY during Pregnancy” (https://doi.org/10.1007/s11892-018-0982-8), describes specific considerations related to maternal glycemic control, fetal mutation status, transplacental transfer of medications, and the need for large, prospective studies to better define management in this setting.

    Has TCOYD ever offered a professional education session on MOYD? If not, please consider doing so!

    • Hi Dr. Baum,
      I don’t believe we’ve ever offered a professional education session on MOYD, but I will definitely share with Dr. Edelman and our continuing medical education team. Thank you for your comments and suggestion!

      • Dear Lynne,

        Thank you for your response and for sharing my request with Dr. Edelman and your CME team for TCOYD to consider offering professional education on MODY.

        I’m a big fan of TCOYD, having attended an extremely high quality TCOYD training here in Albuquerque a number of years ago that I found very helpful both personally and professionally. As a well-respected provider of diabetes education for both professionals and people living with diabetes, TCOYD would be perfectly positioned to increase awareness around the often missed diagnosis and appropriate management of MODY.

        Please let me know if there is any way I could contribute to TCOYD’s offering professional education on MODY, which I would consider an honor.

        Sincerely,
        Susan

  2. My son was diagnosed at age 1, and now he and his fiancee bought a house and are contemplating kids. With a mother who is a researcher, he has access to genetic information, but this won’t stop them. He has a great life and career, and he watched this future grandma put his aab+ brother on a cocktail which derailed diagnosis. I hope all future moms take D3 and high dose O-3 and optimize the child’s AA/EPA ratios. See our study at grassrootshealth.net/t1d and read the stories at http://www.preventt1d.org. He also built his own APS – so can’t wait to hold future grandbabies! Oh, and we will bank cord blood along with protective supplementation…just in case….

  3. Did you consider the choice of adopting a kid?

  4. Hello I diagnosed at 24 but my son born one year before my diagnosis can it come or transfer to him or not please reply

    • Type 1 is hereditary, but your son has an extremely low chance of getting it. It is possible because you have type 1 in your genes, but try not to worry, the chances are low.

  5. I found out I am 5 weeks pregnant. My husband is type 2 diabetic is there a chance that the baby will be diabetic?

    • The baby will not be, but because type 2 typically comes on later in adulthood, your son or daughter will be more at risk for developing type 2 later in life (not as a baby). Keeping his or her weight normal and helping to stay active will be the best prevention.

  6. My T1 history upends any of the probabilities:
    First in our family was my son who developed T1 at age 12. Next was my other son who developed T1 at age 25. Next to develop T1 is myself who developed it at age 49! Go figure!

    • Holy cow, Cindy – wow! Hope they give you a discount at the doctor’s office!

  7. Trying to understand more. If my Mom (diagnosed at 6) little sister (diagnosed at 5) and older brother (diagnosed at 27) all have type 1 what would the chances be for myself my younger brother (who’s now 16) or my children developing type 1 especially if I (26yrs old) don’t have diabetes.

    Next question is if my husband has family history of type 2 then on my side I have type 1 as explained above then type 2 developed in my grandparents late in life (moms parents) does that INCREASE the chances of type 1 or 2 diabetes in my children or myself?

    I wish there was genetic testing for this!!

  8. Recently my wife’s uncle and auntie (both in their 40) from my wife’s mom got diagnosed with diabetes. They are obessed

    Their father also have diabetes in age of about 70 and passed because of complication

    My wife’s mom age is 50 and she is okay because she is pretty strict with her diet (red rice no sugar)

    I am worried about my wife will she inherit diabetes type 2 and our 4 month old son

    • Your wife and child will be more at risk for developing type 2, but keeping their weight normal and staying active will be the best prevention.

  9. Dr. Edelman,

    Do you know of any immunotherapy trials for children who are at risk? I was diagnosed with T1 at age 29, I had my first child at 32 (4yr old) and second child at 36 (9mo old). I have submitted for a blood test kit from Trialnet to test for autoantibodies in the 4 yr old but I’d like to be proactive.

  10. My son was was diagnosed with type 1 diabetes at age 27 that’s almost 2 years ago he is hesitant to have children because he thinks he may be able to pass it on to his children. My mom always told me that Grandma was diabetic she never told me whether she was type 1 or type 2 and she told me that it usually skips a generation which would have been her she’s hypoglycemic and she thought it would be myself or my brother to get it. I had gestational diabetes when I was pregnant with my son and followed the diet for that. What are the odds of him having a child possibly two children what are the odds of them having type 1 diabetes? He had mentioned the thought that this usually comes up as a childhood diabetes but luckily it didn’t happen to him until he was 27 he couldn’t bear the thoughts of his children having to go through this. I want him to be able to have children without worry they’ve made such great parents. Is there any way you could put my mind or his mind to ease that it’ll be okay for him to have children. Please respond. Thank you Angie

    • Dear future grandma, do not worry. If his wife doesn’t have type 1, then their offspring would have approximately 5-8% chance of getting type 1.

  11. I have type 1 from age18 and now l’m 40 years old. Beside this, I have autoimmune thyroid also diagnosed at age 18 and total alopecia from age 14.
    My wife have type 1 from age of 17 and now she is 35 years old.
    We’ll love to have a baby, but we are afraid for rhe baby health condition. We read lots of articles but I hope you’ll help with your advice. What would be the risks for the baby?

    Thank you in advance!
    BR,
    Gabriel

    • The overall risk really depends on some of the details of your and your wife’s genetic makeup. The risk of your child having type 1 can be quite variable based on that genetic information. There are centers around the country that can help you with that analysis.

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