Dr. Joshua U. Klein, United States
     
3.9
Consultations 23
Reproductive Medicine
Doctor Introduction

Dr. Joshua U. Klein, United States


Joshua U. Klein, MD, FACOG

 

Reproductive Endocrinologist and Chief Clinical Officer

 

Co-Founder, Chief Clinical Officer, Reproductive Endocrinologist, and Medical Director of the Embryology Laboratory

 

Dr. Klein is a board-certified reproductive endocrinologist and assistant professor of Obstetrics, Gynecology and Reproductive Science at the Icahn School of Medicine at Mount Sinai. He earned his medical degree at Harvard University and completed his residency in obstetrics, gynecology, and reproductive biology at Massachusetts General Hospital and Brigham and Women's Hospital. He completed a fellowship in reproductive endocrinology and infertility at Columbia University and is board-certified in obstetrics and gynecology and reproductive endocrinology and infertility.

 

Before leading Extend Fertility Medical Practice, Dr. Klein practiced for several years at one of the largest academic IVF programs in the United States, where he served as medical director of Reproductive Medicine Associates of New York in Brooklyn. Dr. Klein has authored and co-authored publications in leading peer-reviewed academic journals such as Science, Fertility and Sterility, and Obstetrics and Gynecology. He has also written numerous medical textbook chapters and presented research at national meetings, including the American Society for Reproductive Medicine (ASRM).

 

Dr. Klein serves on the medical boards of several fertility advocacy organizations and regularly gives lectures and presentations to community groups on infertility and fertility preservation. He is a Castle Connolly Top Doctor and has been named a Super Doctor every year since 2017.


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Location and Hours
200 W 57th St #1101, New York, NY 10019
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  • Monday

    07: 00 - 17: 00

  • Tuesday

    07: 00 - 17: 00

  • Wednesday

    07: 00 - 17: 00

  • Thursday

    07: 00 - 17: 00

  • Friday

    07: 00 - 17: 00

  • Saturday

    07: 00 - 12: 00

  • Sunday

    07: 00 - 12: 00

  • Closed Now
    Affiliated Clinics
    Extend Fertility, United States
         
    • Reproductive Medicine
    Hours: 07: 00 - 17: 00
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    Featured Reviews
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    Jan 7, 2025
    I had an absolutely wonderful egg-freezing experience with Extend. I had previously completed a cycle at another clinic, and the experiences were night and day! My doctor, Valerie Shafran, was wonderful. My treatment plan felt highly personalized, and she made me feel like a real patient rather than another number. Dr. Abittan performed my retrieval and was also amazing! The entire team put me at ease, and I had very positive results. I would definitely recommend this clinic and the entire team.
    Dec 16, 2024
    I worked with Dr. Klein. He and the clinic staff, phlebotomists, and sonographers were knowledgeable and kind. I previously had a retrieval at Genesis Fertility, where the standard of care was much lower. My results at Extend were also far better than at Genesis. Overall, Extend was a good experience, but communication was inconsistent. Communication with my Extend advisor was poor, and at times I did not receive all the information I expected. If you are considering a retrieval, I strongly recommend consulting several doctors and clinics and doing your research. Egg retrieval is physically, emotionally, and financially demanding. Multiple people are responsible for your care, so understanding your situation and knowing how to advocate for yourself helps the process go smoothly. I think Extend is better than some other options, but in my experience there were still problems, and I had to take care of myself and conduct my own research.
    Nov 16, 2024
    I had a very pleasant experience at Extend. From the beginning, the process felt smooth and supportive. After my consultation, I was paired with an advisor who guided me through the next steps and made sure I knew what to expect. The nurses were wonderful, very friendly, and always ready to answer my questions. Most of my scans were performed by a sonographer who was professional and kind, and my provider always reviewed the results. Overall, I am very happy with my decision to freeze my eggs here. The entire process felt manageable, and I felt genuinely cared for at every step.
    Nov 15, 2024
    I hesitated to write this review, but I hope other women are fully informed before making a financial and medical commitment to this provider. My main priority was finding a doctor and team who would communicate with me, help me understand every step, and treat me like a person. Initially, Dr. Klein seemed to meet both needs because he spent an hour learning about my case and educating me. I was assigned a patient coordinator, Avigayil, whom I could ask questions. When I was ready to begin nearly 5 months later, I called Avigayil and received help with a sensitive situation. I appreciated the injection class, especially as someone anxious about needles. Once the process began, however, I became much less satisfied. During the first 8 days of monitoring, I saw no one except the phlebotomist and ultrasound technician. After blood tests and ultrasounds, a different nurse called every few days with instructions. These were brief conversations, and every question required follow-up, which did not inspire confidence. Avigayil did not check in. I wanted to understand why decisions were made and how my progress compared with initial expectations, but I did not receive that information. On day nine, I was given two different sets of trigger-shot instructions and had to call repeatedly and email Dr. Klein for clarification. By then, I had not spoken or communicated directly with Dr. Klein for more than five months. A nurse said she asked him to call because he should have seen me at least once during my monitoring visits, but I received no call, only an email response several hours later. On the morning of my retrieval, Dr. Klein arrived nearly an hour late for my procedure, although I was the first retrieval of the day, and spoke with me for about 30 seconds before I entered the operating room. I have undergone several surgeries and procedures, and this was the first time I felt treated like a box to check or a number on a page. A little humanity would go a long way, especially in such an emotional field, but I found almost none here. Other reviews clearly show that some people have positive experiences here. However, I would warn friends or colleagues against Extend Fertility because they risk having the experience I did. In New York, I am sure you can find a capable practice that offers the humanity and communication you deserve during such an intimate process.
    Nov 14, 2024
    The 2 stars, which should be fewer, are for the administrative staff's disorganization and lack of attention before, during, and after the visit. I encountered many problems. Receptionists, coordinators, and nurses did not communicate with one another about next steps or follow up, and they made phone calls while I stood at the front desk. I had to wait a long time between steps, which was acceptable, but whoever received me next seemed unaware that I was there or why. There appears to be internal dysfunction and a lack of operating procedures, making me wary of using this clinic for anything beyond an initial consultation. 5 stars for Dr. Olcha, who was very clear, knowledgeable, and professional. He is the only reason I would consider returning to Extend after the consultation and testing. (Edit) In response to the business owner: I would be happy to share more. Please feel free to contact me directly.
    Feb 26, 2025
    Although my interactions with the clinic staff were fine—they were friendly and responsive—I want to share my experience with women considering this clinic. I had an egg retrieval with Dr. Klein, and a few hours later I had to go to the emergency room to be evaluated for internal bleeding. After returning home, I developed vomiting and nausea and fainted. My hemoglobin dropped to 8, and I remained in the emergency room for monitoring. It took 3 weeks to recover fully and feel normal again. The staff called and scheduled one follow-up monitoring appointment, but they were somewhat dismissive about what may have happened or what went wrong during the procedure. I do not know how often this occurs at this clinic, as complications can arise with any procedure, but I wanted to share this with anyone considering the clinic.
    Feb 25, 2025
    Feb 10, 2025
    Do not come to this clinic. They were unprofessional in many ways. All my tests indicated that I could retrieve approximately 20 eggs. Then, two days before my procedure, they said my numbers were poor. It turned out that the doctor had not given me enough medication. I could not believe it. They did not even apologize and tried to blame me, suggesting that perhaps I had not followed the injection instructions. It was a terrible experience! They were unkind and irresponsible, and most importantly, they made me feel uncomfortable as a woman in an extremely vulnerable situation.
    May 5, 2025
    Words cannot express how grateful we are to the entire Extend Fertility team. We spent more than four years at another clinic with no answers and a finish line that kept moving. At our previous clinic, we were treated as customers rather than patients. From our first consultation with Extend, the difference was tremendous: we felt supported, informed, and genuinely cared for. The doctors took time to explain every step of the process, and the nurses were compassionate and encouraging at every appointment. These treatments are very expensive, and the billing staff work hard to ensure that insurance covers what it should and/or communicate out-of-pocket costs in advance. If you are looking for a fertility clinic that combines expertise with empathy, this is the place. We highly recommend them!
    May 3, 2025
    Sep 7, 2025
    I would not recommend Dr. Klein or this clinic. We paid more than $400 for a consultation, only to be seen over an hour after our scheduled appointment. When we finally met the doctor, Dr. Klein did not apologize, even though we were clearly upset. He seemed distracted, avoided eye contact, and was rude. After the appointment, I sent my medical records along with a follow-up email but never received a response. I called the clinic and was told to resend everything because "Dr. Klein is not good with email." Given the cost and importance of fertility treatment, this level of care and professionalism is unacceptable. Dr. Klein is not included on any reputable "best doctor" lists, and based on my experience, the reason is clear. I strongly recommend seeking care elsewhere.
    Oct 15, 2025
    Dec 1, 2025
    Unfortunately, I cannot recommend this practice. Its website emphasizes fertility preservation and freezing, but the clinic told me that single men are not eligible for this already difficult-to-access, highly specialized service.
    Feb 1, 2026
    Feb 1, 2026
    You care more about your money than your poor customers; a total lack of respect.
    Mar 15, 2026
    Nice place. Jeffrey Epstein stored his embryos here...
    Apr 24, 2026
    A very disappointing experience. The appointment felt rushed and impersonal, and the doctor seemed more focused on promoting other services than providing clear, personalized guidance. After receiving concerning test results, my partner and I felt confused and unsupported. Communication afterward was also poor. We had to ask for our results, the timeline was unclear, and the doctor never provided proper follow-up. Meanwhile, they contacted us quickly about payment, which felt inappropriate given the lack of care. Overall, we did not feel supported or valued as patients and would not recommend this clinic.
    Apr 23, 2026
    May 3, 2026
    My experience was terrible. Although the doctor repeatedly told me that based on my AMH and other indicators, I should retrieve at least 15 eggs, I ultimately retrieved only 6. Worse, the anesthesiologist asked whether I had considered a hysterectomy while I was undergoing a procedure intended to do the exact opposite. This frightened me greatly, and I would not recommend this procedure to anyone.
    Apr 25, 2026
    Extend Fertility is absolutely one of the best fertility clinics I have experienced. From the moment I entered, every staff member made me feel comfortable, reassured, and genuinely cared for. The clinic is clean, modern, welcoming, and relaxing. Everyone is professional, knowledgeable, and patient. They take time to explain every step in detail, answer every question, and ensure that you never feel rushed. I also appreciate how organized and efficient the clinic is—from scheduling and laboratory testing to follow-up, everything runs smoothly. Communication is excellent, and they respond quickly whenever I need help. What distinguishes Extend Fertility most is its compassion and understanding. The team genuinely cares about your goals and supports you at every step toward success. I highly recommend Extend Fertility. Their professionalism, kindness, and expertise are second to none.

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