Short answer: no. ICSI cannot choose your baby's sex, and in the UK nor can anything else a licensed clinic is allowed to offer, unless a serious sex-linked medical condition is involved.
That is worth saying at the top, because a lot of what you will read on this subject is written for readers in countries with different laws, and it leaves people hopeful about something a UK clinic cannot do.
A note on wording: clinically this is about a baby's sex, meaning the X and Y chromosomes, rather than gender. People usually search for “gender”, so that is the word in the title, but sex is the accurate term for what testing can see.
ICSI stands for intracytoplasmic sperm injection. It is a laboratory step within an IVF cycle. In unassisted conception a single sperm reaches and enters the egg on its own. With ICSI, an embryologist selects one sperm and injects it directly into a mature egg.
It is usually recommended where fertilisation is the problem rather than the eggs:
ICSI improves the chance that an egg fertilises. It does not change an embryo's genetics, and it does not influence its sex.
An embryo's sex is set at fertilisation. The egg always contributes an X chromosome. The sperm contributes either an X, giving XX, or a Y, giving XY. So the sperm decides it.
When an embryologist chooses a sperm for ICSI, the selection is made on what can be seen down a microscope: shape, movement, apparent quality. Whether that sperm carries an X or a Y is invisible. There is no way to tell, and no evidence at all behind the popular idea that faster or stronger sperm produce boys.
If your treatment plan includes ICSI, your baby's sex is determined exactly as it would be in unassisted conception.
Preimplantation genetic testing (PGT) analyses a few cells taken from an embryo at around day five. PGT-A counts chromosomes, and because sex is carried on the X and Y chromosomes, the count reveals whether an embryo is male or female.
So the information can exist. Acting on it is the part UK law prohibits.
The Human Fertilisation and Embryology Act 1990, as amended in 2008, states at Schedule 2, paragraph 1ZB:
A licence under paragraph 1 cannot authorise any practice designed to secure that any resulting child will be of one sex rather than the other.
The Human Fertilisation and Embryology Authority (HFEA), which licenses every UK clinic including ours, puts it this way: “UK law is very clear that selecting the sex of your child for any reason other than preventing serious inherited illness is strictly prohibited.”
There is one exception. Sex selection is permitted where there is a particular risk that a woman will give birth to a child who will have or develop a serious physical or mental disability, illness or medical condition that is gender-related, meaning the HFEA is satisfied it affects only one sex or affects one sex significantly more than the other. X-linked conditions such as Duchenne muscular dystrophy and haemophilia are the usual examples: boys are affected, girls are usually carriers.
Even then it is not the clinic's call. The HFEA approves embryo testing condition by condition and publishes the list.
Because none of this can lawfully influence which embryo is transferred, patients having PGT-A in the UK are not routinely told the sex of their embryos at all.
Some clinics outside the UK do offer sex selection for social reasons. The HFEA cannot regulate treatment abroad, but it has said it would be “extremely concerned about any HFEA licensed centre, or any individual connected to it, promoting and facilitating such treatment.” We will not arrange it or refer you for it.
If ICSI is right for you, it is right for reasons to do with fertilisation, and those reasons are worth understanding properly. Our page on ICSI sets out when it helps and when it does not, and every price is published on our prices page so you can see the cost of adding it before you commit to anything.
Where we can be useful is telling you honestly whether ICSI is likely to make a difference for you, rather than adding it as a matter of routine. Where we cannot help is choosing your baby's sex, and we would rather you knew that before you booked anything.
No. ICSI injects one sperm into an egg, but nobody can see whether that sperm carries an X or a Y chromosome. Sex is still determined at fertilisation, as it would be naturally.
Testing can identify an embryo's sex, but in the UK that information cannot lawfully be used to decide which embryo is transferred, except in the narrow medical circumstances above.
No, and the differences are large. Several countries permit it for social reasons; the UK does not. Much of the material you will find online is written for readers elsewhere.
It improves the chance of fertilisation where sperm quality is the obstacle. Where fertilisation was never the problem, adding ICSI does not improve your chance of a baby, and we will say so rather than charge you for it.
ICSI is well established, but it is an additional laboratory procedure and not entirely without risk. Our team will go through what is known, and what remains uncertain, in your own situation.
If you would like to understand what would actually help you, start with a free 15-minute consultation with a Fertility Specialist. No referral needed, and no obligation. Book a free consultation.
