Let's be direct: biologically, a female cannot get pregnant without sperm. Whether it's through natural intercourse or medical procedures like IVF/IUI using a donor, male sperm is essential.
True, biologically a female egg needs a male sperm to cause pregnancy. If you are asking about IVF or donor sperm, that's a different process altogether.
Pregnancy naturally requires both male sperm and a female egg to happen. It's a beautiful process of two cells coming together, which then grows into a healthy baby.