Meghan has been accused of lying about her "rags to riches" upbringing by her half-sister Samantha in court documents.
Samantha is suing Meghan for allegedly peddling the story in her high-profile Oprah interview, broadcast in 2021.
The Duchess' lawyers have made their counter-argument in legal documents filed in Florida.
In the most recent papers, Meghan's team dispute Samantha's assertion that it was dishonest for the royal to claim she grew up as an only child, claiming it is how she feels despite her technically having two half-siblings.
Meghan with husband Prince Harry in New York
BRENDAN MCDERMID
Meghan Markle
DYLAN MARTINEZ
Her team point out: "It is hard to imagine a more personal and subjective feeling than how one views their own childhood.
"Moreover, Plaintiff's opposition completely ignores the context of the statement, where Ms Winfrey asked Meghan about her 'relationship' with Plaintiff (to whom Ms Winfrey referred as her 'half-sister on her father's side').
"Meghan's response to that question that she 'grew up as an only child' was obviously not meant to be a statement of objective fact that she had no genetic siblings or half-siblings."
It comes as Meghan reportedly feels that Tom Bower’s newly released biography is “uncalled for” as she and Prince Harry continue to process the “highly stressful” situation.
Mr Bower released the biography titled 'Revenge: Meghan, Harry and the War between the Windsors' last Thursday.
Within the book, Mr Bower revealed several damning stories against Meghan and her relationship with Harry.
Among the stories included the Duke and Duchess of Sussex being involved in a “monumental row” ahead of the 2020 Commonwealth Day Service at Westminster Abbey.
Samantha released a book about her sister last year titled The Diary of Princess Pushy's Sister: A Memoir, Part One.
It details the Markles' upbringing, including the rivalry when their dad Thomas was still married to Doria Ragland.
Samantha also writes of her adoration for Meghan as a baby and described the infant as "bi-racial, beautiful, and was both the colour of a peach, and a rose".