Bible biology is always a complex matter.  If there were no complexities in bearing children (like a sterile woman) what use would we have of God? Take the case of Jacob and Esau. They would not exist without the intervention of a loving God. Well, one might have to understand that God is loving but also has a sense of humor. Check this out:

Jaclyn Glenn is to be commended for her participating in playing several female roles in this video. Also, please check out this site: darkmatter.spreadshirt.com for great opportunities. These folks epiitomize the sense of humor of their Creator.