In a compilation of public comments for submission to the House of Representatives' Committee on State Affairs in October 2023, Mindy Phillips of Prosper, Texas, makes the implicit claim that COVID-19 vaccines cause cancer. Mindy provides no backing sources or details about preexisting health conditions, timing or type of vaccine, etc.
This claim draws upon the "turbo cancer" conspiracy theory that developed during the pandemic, alleging that the COVID-19 vaccine (mRNA in particular) caused rapid cancer growths in vaccinated individuals.
Reuters, the American Cancer Society, and the NIH National Cancer Institute have found no evidence that COVID-19 vaccines cause cancer. Reuters includes statements from various immunology experts and cancer researchers from the John Hopkins Center for Health Security, Imperial College London, University of Edinburgh and more. The American Cancer Society asserts "there is no information that suggests that COVID-19 vaccines cause cancer."
Peer-reviewed studies also indicate vaccination amongst pregnant individuals is not correlated with miscarriage (Yale School of Medicine), nor major structural birth defects (NIH National Library of Medicine).
In sum: Mindy's claim that her sister received the COVID-19 vaccine and delivered a baby with cancer may be true (I was unable to find enough information on Mindy to confirm her personal anecdote). However, no evidence exists to directly correlate the vaccine and cancer. This claim can be classified as misleading, as Mindy falsely equates her personal story with a broader scientific untruth.