Paternity tests
A few years ago, any doubt regarding the true parent ship entailed a long and costly legal process that culminated with the acceptance or refusal to carry out the test to confirm or not the parenting.
Currently, an industry that has flourished solves this problem by a large number of paternity tests that can be performed even at home, sending samples by post.
While traditional paternity test is forced a bloody sampling (blood), now just a buccal swab (gently scrape the inside of the cheek with a thrush) is enough for the sample.