Final answer:
Male sperm can survive in the female's reproductive tract for 3 to 5 days after ejaculation. Their journey to the oocyte can take 30 minutes to 2 hours, and if they meet an oocyte within this time frame, fertilization can occur.
Step-by-step explanation:
The viability of male sperm within the female's reproductive tract is a complex biological process. During ejaculation, the male releases hundreds of millions of sperm into the female's vagina, where many face challenges such as the acidity of the vagina and the barrier of cervical mucus. However, the strongest contenders reach the uterine tubes, where they may encounter an oocyte.
The journey of the sperm is thought to be facilitated by uterine contractions and can take from 30 minutes to 2 hours. Should sperm not immediately meet an oocyte, they are capable of surviving in the uterine tubes for another 3 to 5 days. This allows for the possibility of fertilization if intercourse happens a few days before ovulation since an oocyte is viable for only about 24 hours post-ovulation.