SISTER: Sibling Oocyte Insemination With Frozen Sperm From Third Party Donors: Evaluation of Reproductive Techniques

The goal of this clinical trial is to learn whether two different methods of helping eggs and sperm join-intracytoplasmic sperm injection (ICSI) and conventional in vitro fertilization (IVF)-lead to better embryo development when using frozen donor sperm in people who do not have male fertility problems. The main questions it aims to answer are: Does one method create more usable embryos (blastocysts) than the other? Is there a difference in how often fertilization does not happen at all? Do either of the methods lead to better embryo quality or early pregnancy? Participants will: Have their eggs divided into two groups. One group will be fertilized using ICSI (where a sperm is injected directly into an egg), and the other using conventional IVF (where eggs are mixed with sperm in a dish). The fertilization method for each egg will be randomly assigned, with a random process also used to determine the assignment of any extra egg when an odd number is collected. Continue regular fertility treatment while the study team compares the results of each fertilization method. This study includes people with non-male factor infertility and uses frozen donor sperm. It hopes to learn whether ICSI, which is often used even when it may not be needed, truly helps improve outcomes compared to conventional IVF in these cases.