Still, on the topic of illegitimacy when proven by way of a Y-DNA test, there are several unanswered questions of great importance:
Take the case of a child born to a married woman where the biological father is not the woman's husband, and the woman keeps this a secret. When this "mis-attributed paternal event" is finally discovered via DNA (as it will be more and more in the future), the question still remains: How would you list the biological father on the family tree? Clearly, 50% of the child's genes are from the biological father (while 0% are from the woman's husband).
In addition, the child will carry the legal last name of the husband (not the biological father) throughout his/her life. How would you then list the husband in relation to the child (given the husband is listed on the birth certificate, not the biological father)?
Also, do DNA tests override documentation? How can they not? Family history is one thing, but genealogy is inherently about one's "genes". Is this where "family history" diverges from ancestry? As more and more people in more and more counties take DNA tests, and as databases grow larger and technology more advanced, consider this: Ten years from now how many "genealogies" will be "proven" to be inaccurate? Will this not result in years of "genealogical" conclusions being thrown into question.
Are any of us prepared for what we might find - all those family secrets that were never meant to be found out? What will be the process for confronting parents/grandparents, and newly found parents/grandparents, by the children that lived their lives believing dad was dad, only to find out that he wasn't?
And lastly, how will we cite sources for DNA matches (many that may be still alive) that have provided the evidence needed to prove mis-attributed paternal events? Where does the genealogical proof standard end and confidentiality ethics supersede?