Medical Oncologist
CION Cancer Clinics
Planning a family when you carry an RB1 fault | CION Cancer Clinics
If you carry an RB1 fault, each child you have has a one in two chance of inheriting it. You still have real choices. Some couples conceive naturally and have the baby's eyes checked from birth. Others test during pregnancy or test embryos through IVF. This page explains each option, what it involves in India, and who to speak to before you start. At CION Cancer Clinics, our oncologists explain what a gene result means for you and your family, and plan the checks that follow.
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Medically reviewed by Dr. Naresh GunduConsultant Medical Oncologist · MBBS, DNB (Internal Medicine), DM (Medical Oncology, AIIMS) · last reviewed September 2026, next review due September 2027
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On this page
- Can you have healthy children if you carry an RB1 fault?
- What options do couples actually have?
- What should you do before trying for a baby?
- The words you will meet, in plain language
- Checking after birth or testing before it: how do they compare?
- Four things families tell us, and what is actually true
- What this page cannot tell you
- Common questions about RB1 and having children
The short answer
Can you have healthy children if you carry an RB1 fault?
Yes. Many retinoblastoma survivors and carrier parents go on to have children, and most of those children keep their sight. Each pregnancy carries a one in two chance that the baby inherits the fault, so planning is about finding it early or choosing not to pass it on.
Why the chance is one in two
You have two copies of the RB1 gene, one from each parent. If one copy is faulty, each egg or sperm you make carries either the faulty copy or the working one. It is a coin toss for every pregnancy. A child who has escaped it does not change the odds for the next child.
What inheriting it means for a baby
Most babies who inherit an RB1 fault develop retinoblastoma, an eye cancer of early childhood, often in both eyes. Found early through planned eye checks, tumours are usually small and treatable, and the eye and its sight can often be saved. Found late, the picture is very different. That gap is the whole reason to plan ahead.
Some families carry a milder RB1 variant where fewer children develop tumours. Only your counsellor can tell you which kind your family has.Your choices
What options do couples actually have?
None of these is right for everyone. Couples choose differently, and some change their minds between pregnancies.
Conceive naturally, check from birth
The most common path. The baby is tested soon after birth, and eye examinations start in the first weeks of life while the result is awaited.
What it involves
- No procedure during pregnancy
- A strict eye check schedule in early childhood
- Easiest to follow near a specialist eye team
Test during the pregnancy
A sample from the placenta or the fluid around the baby is tested for the family's exact fault. Knowing early lets the eye team and the obstetrician plan the delivery and the first checks together.
Test embryos before pregnancy
Through IVF, embryos are tested for the fault and one without it is placed in the womb. This is called preimplantation genetic testing. It is costly and can take more than one attempt.
Donor egg or sperm, or adoption
Using an egg or sperm from a donor who does not carry the fault removes the chance of passing it on. Some couples choose adoption. A counsellor will talk these through without pushing you either way.
Not sure whether this applies to you?
Ask an oncologistBefore you try
What should you do before trying for a baby?
Find the exact fault
Every option depends on knowing the precise RB1 variant in your family. If the survivor was never tested, that test comes first. It usually needs only a blood sample.
See a genetic counsellor together
Go as a couple. The counsellor explains the chance for each pregnancy, whether your variant is a milder kind, and each option in plain language, in Telugu if you prefer.
Choose without a deadline
Take the time you need. Embryo testing needs months of preparation, so start the conversation well before you plan to conceive.
Plan the birth with the eye team
Tell your obstetrician early. Arrange the newborn test and the first eye examination before the baby arrives, so nothing waits on paperwork.
On your report
The words you will meet, in plain language
- Heritable retinoblastoma
- Retinoblastoma caused by an RB1 fault present in every cell. It can be passed to children and often affects both eyes.
- Carrier
- Someone who has the RB1 fault. A carrier may be a survivor, or a relative who never had a tumour.
- De novo
- A fault that appeared for the first time in one person and was not inherited from either parent. Once present, it can be passed on.
- Mosaicism
- The fault is present in only some of a person's cells. A mosaic parent can test negative in blood and still pass it on.
- Prenatal diagnosis
- Testing the baby during pregnancy, using a sample from the placenta or the fluid around the baby.
- Preimplantation genetic testing
- Testing embryos made through IVF before one is placed in the womb.
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Side by side
Checking after birth or testing before it: how do they compare?
Checking after birth
Testing before birth
No procedure in pregnancy
A procedure in pregnancy, or IVF before it
The baby may inherit the fault
Passing the fault on can be avoided
Frequent eye checks in early childhood
Checks only if the fault is present
Lower cost at the start
Higher cost, rarely covered by schemes
Commonly believed
Four things families tell us, and what is actually true
"My tumour was in one eye only, so my children are safe."
Some survivors of a one-eye tumour do carry an RB1 fault in every cell. Only a blood test on the survivor answers this. Until it does, their children are usually checked as if they are at risk.
"Neither of us had eye cancer, so our next baby cannot get it."
A parent can carry the fault in some egg or sperm cells without ever having a tumour. That is why brothers and sisters of an affected child are usually checked too, even when both parents test negative.
"Any testing in pregnancy is illegal in India."
The PCPNDT Act bans finding out the sex of a baby. It regulates genetic testing in pregnancy and allows it only at registered centres. The ART Act separately allows embryo testing for known inherited diseases.
"It is better not to tell the other family before the marriage."
Families often fear that telling will harm a match. Yet every option on this page depends on both partners knowing before a pregnancy begins. A counsellor can help you plan how and when to have that conversation.
Being straight with you
What this page cannot tell you
It cannot tell you which option is right for you. That depends on your variant, your age, your finances, your beliefs and how you feel about each path. A genetic counsellor can set these out clearly. The decision stays with you and your partner.
It cannot read your report
What your specific variant means is a question for the counsellor who ordered the test. RB1 variants differ. Some lead to tumours in almost every child who inherits them, and some far less often. That difference changes how families weigh these choices.
Who this does not apply to
If a survivor had a tumour in one eye and a careful blood test found no RB1 fault, the chance for their children is much lower. Their plan is usually lighter, and some of these options will not be needed at all. Your counsellor will say how much lower it is for your family.
Start early. Embryo testing and testing in pregnancy both need planning time that cannot be rushed once a pregnancy has begun.Questions we are asked
Common questions about RB1 and having children
What is the chance my child will inherit RB1?
One in two for each pregnancy, if one parent carries the fault in every cell. The odds reset every time, whatever happened with earlier children. If the parent carries it in only some cells, the chance is lower, and your counsellor will explain what that means for your family.
Can the baby be tested at birth?
Yes. If the family's exact fault is known, a blood sample from the newborn, sometimes taken from the cord, can be tested for it. Eye examinations usually start in the first weeks anyway. A negative result normally ends the need for frequent eye checks.
Is IVF with embryo testing available in Hyderabad?
Several fertility centres in Hyderabad offer IVF with preimplantation genetic testing. The family's exact variant must be known first, and the laboratory has to design a test for it, which takes time. Costs are high and rarely covered by schemes.
Does testing during pregnancy put the baby at risk?
The procedures used to take a sample carry a small risk of miscarriage. The fetal medicine specialist will explain the risk at their centre. Some couples test only to prepare for the birth. Others would consider ending the pregnancy. Both are valid choices.
Can a father pass on RB1?
Yes, in exactly the same way as a mother. The chance for each child is the same whichever parent carries the fault. Fathers treated for retinoblastoma as small children sometimes do not know their own history, so asking older relatives helps.
My partner does not carry RB1. Does that lower the chance?
No. One faulty copy is enough, so a child's chance depends only on the parent who carries it. Your partner's genes do not dilute or cancel it. Your partner usually does not need an RB1 test unless there is a separate family history.
Will insurance or a scheme cover fertility treatment?
Most insurance policies and government schemes do not cover IVF or embryo testing. Check your policy wording and ask the fertility centre for a written estimate. Newborn testing and eye examinations are usually far cheaper, and some of that care may be covered.
When should we start this conversation?
Before you try to conceive, ideally several months before. Embryo testing needs time to prepare, and testing in pregnancy must happen within a set window. Starting early keeps every option open and means no decision has to be made in a hurry.
Your Specialists
Meet CION's oncologists. Bring your family history or genetic report to them.
Our medical oncologists see people with a strong family history of cancer, arrange genetic counselling and testing where it fits, and plan the checks that follow.
Medical Oncologist
Dr. C. Raghavendra Reddy
MBBS(Gold Medal), DNB(General Medicine), DM(Medical Oncology)(Gold Medal)
Medical Oncologist
Dr. Bharati Devi Gorantla
MBBS, MD(General Medicine), DM(Medical Oncology)(Adyar,Chennai), ECMO, MRCP SCE(UK)
Medical Oncologist
Dr. Owais Mohammed
MBBS, MD (General Medicine), DrNB (Medical Oncology), ECMO, MRCP SCE (Medical Oncology) (UK)
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Sources
- GeneReviews (NCBI) — Retinoblastoma
- MedlinePlus Genetics — Retinoblastoma
- MedlinePlus Genetics — RB1 gene
- National Cancer Institute — Retinoblastoma Treatment (PDQ) – Patient Version
This page is general information, not a prescription. Do not change or stop any treatment based on what you read here. If anything is worrying you, contact your own treating team — or call our helpline and we will help you reach the right specialist.
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Planning a family and not sure where to start?
Tell us what you know about the RB1 result in your family. We will arrange genetic counselling and explain your options without any pressure. One helpline serves every CION centre.