What does it mean that Dr Marren is CREI-certified?

CREI stands for Certified Reproductive Endocrinologist and Infertility Subspecialist. It is the highest level of postgraduate training in fertility medicine in Australia, requiring three additional years of advanced subspecialty training beyond FRANZCOG. A relatively small number of fertility specialists in Australia hold this credential. For patients, it means Dr Marren has extensive, specific expertise in the most complex areas of fertility care, including genetic testing, recurrent loss, and advanced reproductive surgery.

Can Dr Marren provide a second opinion if I have already had treatment elsewhere?

Yes, and Dr Marren actively welcomes second opinion consultations (https://anthonymarren.com.au/fertility-treatment-second-opinion-sydney/). He reviews all previous investigation and treatment records before the appointment so the consultation is focused and productive. He approaches these cases without judgment toward previous care teams. The goal is to identify what might not yet have been explored and to give you a clear, honest picture of what the evidence supports for your specific situation.

Why did Dr Marren choose to partner with Genea?

Dr Marren has spoken directly about this: his decision to partner with Genea was driven by their commitment to research and development, and by the consistently high standards of their laboratory and clinical programmes. As Medical Director of the Sydney CBD clinic, he is closely involved in the quality of care and the technology used there.

Does Dr Marren have particular expertise in male infertility?

Yes. Dr Marren consistently emphasises that male factors account for 30-50% of cases in couples having difficulty conceiving, and he investigates both partners from the outset. He routinely requests sperm DNA fragmentation testing and, where the semen analysis is abnormal, pursues a full hormonal and genetic workup. He also performs surgical sperm retrieval techniques, including microTESE.

What days is Dr Marren available?

Dr Marren consults Monday to Saturday at Genea Sydney CBD and Genea St Leonards. Both in-person and telehealth consultations are available.

Genea Fertility Australia

Q: What is preimplantation genetic testing and is it something Dr Marren recommends?

Preimplantation genetic testing (PGT: https://www.genea.com.au/pages/preimplantation-genetic-testing-pgt-m-pgt-a-MCURWXKU5I55GXZBJMS7SZH6R7TY) allows embryos to be assessed for chromosomal abnormalities or specific genetic conditions before they are transferred during IVF. Dr Marren completed a Master of Medicine in Reproductive Health and Human Genetics and has a genuine specialist interest in this area. PGT may be recommended for patients with recurrent pregnancy loss, recurrent IVF failure, advanced maternal age, or known genetic conditions. He discusses PGT as part of a thorough assessment of each patient's circumstances, not as a default recommendation.

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Biography

Dr Anthony Marren is a CREI-certified Fertility Specialist and the Medical Director of Genea's flagship Sydney CBD clinic. With advanced subspecialty training in reproductive endocrinology and infertility (CREI), Dr Marren brings particular expertise in recurrent pregnancy loss, recurrent implantation failure, preimplantation genetic testing, and complex fertility cases. He is also experienced in fertility preservation for patients preparing for chemotherapy and other treatments that may affect fertility.

Available for: In-person bookings | Telehealth consultations

Experience and qualifications

Dr Marren holds a medical degree from the University of Newcastle, where he was awarded the Faculty of Medicine Medal - recognising academic excellence across the B. Medicine program. He went on to complete a Master of Medicine in Reproductive Health and Human Genetics at the University of Sydney.

Dr Marren trained in Obstetrics and Gynaecology at Sydney's Royal Prince Alfred Hospital and is a Fellow of the Royal Australian and New Zealand College of Obstetricians and Gynaecologists (FRANZCOG). He holds the additional CREI credential - Certified Reproductive Endocrinologist and Infertility Subspecialist - which requires a further three years of advanced subspecialty training in fertility medicine beyond FRANZCOG. CREI represents the highest level of postgraduate training available in reproductive medicine in Australia.

As a skilled laparoscopic surgeon, Dr Marren performs advanced procedures, including surgery for endometriosis and fibroids. He has extensive experience managing recurrent pregnancy loss, recurrent implantation failure, preimplantation genetic testing, and complex fertility cases. He is also experienced in fertility preservation for patients preparing for chemotherapy and other treatments that may affect fertility.

How Dr Marren can help

Dr Marren works with people navigating a wide range of fertility challenges, including:

General and unexplained infertility
Second opinion consultations for complex or stalled cases
Preimplantation genetic testing (PGT-A, PGT-M, PGT-SR)
Recurrent pregnancy loss
Recurrent IVF failure and recurrent implantation failure
Fertility preservation and oncofertility
Egg freezing
Egg and sperm donation
Surrogacy
Endometriosis, including advanced laparoscopic surgery
Testicular aspiration, biopsy, and microdissection (microTESE)
Ovulation disorders and polyendocrine metabolic ovary syndrome (PMOS)
Premature Ovarian Insufficiency (POI)
Male infertility, including sperm DNA fragmentation testing and sperm retrieval
In vitro fertilisation (IVF) and intracytoplasmic sperm injection (ICSI)

Approach to care

Dr Marren understands that fertility treatment is far more than a medical process - it involves real emotional, financial, and personal stakes. His consultations are a deliberately judgement-free space where he takes the time to listen fully before explaining what the evidence shows and what your options genuinely are. Dr Marren believes that being direct and factual is the most respectful thing he can offer a patient. He sees patients from all backgrounds and family structures, and he consistently investigates both partners from the outset. Dr Marren is known for explaining the science with genuine depth, then translating it into clear, actionable terms that make sense for the person sitting across from him.

"I have dedicated my life to helping people who have always dreamt of starting a family. The science matters enormously, but so does the person in front of me. I want every patient to leave knowing not just what we are doing, but why, and what it means for them." - Dr Anthony Marren, Medical Director Sydney CBD and Fertility Specialist, Genea

Meet Dr Anthony Marren

In this short video, Dr Marren introduces himself and explains what you can expect from a consultation with him. He talks about his specialist focus - fertility medicine for both women and men - and his particular interest in recurrent pregnancy loss, recurrent implantation failure, and fertility-related surgery, including endometriosis, fibroids, and tubal procedures. If you are wondering whether to make an appointment, this is a good place to start.