The main methods of<unk>  are ovarian protection by GnRH agonists, cryopreservation of ovarian tissue, eggs or sperm, or of embryos after in vitro fertilization. The patient may also choose to use egg or sperm from a donor by third party reproduction rather than having biological children. Semen cryopreservation Men hoping to preserve their<unk>  before undergoing treatment for cancer or another<unk> -threatening disease can cryopreserve, or freeze, their sperm, which can be obtained through masturbation in post-pubescent boys and men. This is the most established<unk>  method for males. For pre-pubescent boys, sperm can be obtained through testicular aspiration or electrostimulation and then stored for future use. Researchers are also looking at methods for cryopreserving testicular tissue samples so that they can be re-implanted into the body after treatment. Cryopreservation of ovarian tissue or oocytes Oocyte cryopreservation Oocyte cryopreservation involves the extraction and freezing of a female's eggs, to preserve their viability for future use. This is often due to medical reasons such as females undergoing cancer treatment. It is also increasingly being used for elective<unk>  in females who are not ready to become pregnant but who are conscious of their age-related decline in<unk> . This process is different to embryo cryopreservation, where mature eggs are fertilised in vitro (outside the body) with sperm from a donor or partner, and the embryo is frozen. The religious and ethical concerns and legislative restrictions surrounding embryo cryopreservation has prompted significant technical advances in oocyte cryopreservation techniques. Oocyte cryopreservation is now considered a well-established technique for<unk>  in women. Embryo cryopreservation Some female patients choose to have mature eggs extracted and fertilized outside of the body with sperm from a partner or donor. The resulting embryo is then frozen until the female's is in remission from disease. When the female's is ready to initiate pregnancy, the embryo is thawed and implanted into the uterus for maturation and birth. While this option is the most common<unk>  method in females, it is not available to pre-pubescent girls, who do not have mature eggs that can be fertilized. females who do not have a partner will need to use donor sperm. Additionally, because this procedure requires a two-week period of hormonal stimulation to encourage egg maturation, it is not optimal for female patients who are diagnosed with hormone-sensitive cancers (such as breast cancer, ovarian cancer, etc.) or those who cannot delay cancer treatment. Alternative methods of hormonal stimulation using letrozole or tamoxifen may be used for females with hormone-sensitive cancers. Ovarian tissue cryopreservation Cryopreservation of human ovarian tissue has been successfully carried out around the world to preserve<unk>  in female cancer patients and in other pathologies where the patient is at increased risk of primary ovarian insufficiency. Most notably, this technique can provide an option for<unk>  in prepubertal girls. Part of the ovary is removed, frozen and stored until after treatment. The tissue is then thawed and re-implanted. According to a meta-analysis performed in 2017, the success rate of reestablishment of ovarian activity was 63.9%, restoring normal<unk>  and endocrine function. Over 130 live births have been reported as of June 2017. Strips of cortical ovarian tissue can also be cryopreserved, but it must be re-implanted into the body to allow the encapsulated immature follicles to complete their maturation. Furthermore, ovarian tissue is fragile under hard freezing conditions and putting it back into the body carries the risk of re-introducing cancerous cells. In vitro maturation has been achieved experimentally, but the technique is not yet clinically available. With this technique, cryopreserved ovarian tissue could possibly be used to make oocytes that can directly undergo in vitro fertilization. Third-party reproduction Many patients diagnosed with a malignancy or another disease requiring treatment that may impair their<unk>  consider alternatives to bearing biological children, such as assisted reproductive technology (ART) using in vitro fertilization (IVF) with donor eggs or donor sperm. The resulting embryo can be implanted into the female's's uterus after her endometrium (the lining of the uterus) is stimulated with hormones to prepare for the development of the embryo. Others In females requiring local pelvic radiation therapy may benefit from surgical transposition of the ovaries to a site remote from maximal radiation exposure. The use of GnRH agonists for ovarian protection during chemotherapy is suggested to benefit the ability to ovulate, but benefits in terms of e.g. pregnancy rate are lacking. Table 1: Main Options of<unk>  Method Process Advantages and Disadvantages Further Considerations Oocyte cryopreservation * Halt GAHT (gender affirming hormone therapy) and carry out ovarian stimulation with transvaginal oocyte retrieval. * Cryopreserve mature oocytes. * No sperm necessary at time of retrieval, can be used later for fertilisation. * Clinically available. * Has to be carried out after puberty. * Invasive procedure. * Those with female partners, donor sperm may be required, the embryo can then be transferred to the partners uterus. * Individuals with male partners can use partner's sperm but will need a surrogate to carry the embryo. Embryo cryopreservation * Halt GAHT and carry out ovarian stimulation to harvest oocytes. * Fertilisation of mature oocytes and embryo cryopreservation. * Clinically available. * Need sperm at time of oocyte retrieval. * Has to be carried out after puberty. * Invasive procedure. * Those with female partners donor sperm may be required, the embryo can then be transferred to the partners uterus. * Individuals with male partners can use partner's sperm but will need a surrogate to carry the embryo. Ovarian tissue cryopreservation * Can be carried out at the same time as sex reassignment surgery. * Surgical extraction of ovarian tissue for cryopreservation. * Can be carried out before and after puberty. * No sperm necessary at time of retrieval. * Clinically available. * Don't need to halt GAHT. * Cryopreservation of either an ovarian cortex biopsy or the whole ovary, then the thawing and maturation of the follicles at a later date. * Reimplantation of the tissue and the use of IVF.
Fertility preservation
Fertility tourism
Semen cryopreservation
Assisted reproductive technology
Vas-occlusive contraception
Sex reassignment surgery 
Sex reassignment surgery
Intersex medical interventions