Claire is the child of multi millionaire parents, it's pretty safe to say Claire was an oopsie baby. Her mother is the partner for a highly successful law firm and her father is a neurosurgeon. Her parents kept putting off having children so they could advance in their careers. Eventually they got so busy with their careers that they forgot the idea to have a child.
When Claire's parents were getting to the top of their careers as they got into their late 30s, Claire's mom got pregnant.
Claire was raised to be a lawyer from the get go so the partnership would be passed down to her. Now that her mother is getting closer to retirement age, the pressure is being put on Claire to prepare to be the next partner.