Can I start a profile of a sibling when parents are unproveable?

Question

I was looking for the parents of Lavina Lewis names on the 1850 or 1860 census.  She was not proveably identified on either of them.  Running a scan on a local newspaper source gave me a death article about her as her sister's survivor.  No parents were identified in her sister Tamma Lewis Armin's article.  I tried to enter Tamma as a sibling of Lavina but I am told to establish a parent first.  Where do I go from here?

Comments

By combining the advice of all of you I have established a profile for Tamma Lewis Armin.  A research note exists on each profile.  I decided to not create another unknown with
estimates.

Answer 1

Until there is more information, I would add a note in each profile, referring to the other a sister. And cite your sources.

Answer 2

Yes.  Go to the "Add" menu and choose the menu item "New Person".

Comments

Create the father as Unknown Lewis, with an estimated date of birth or death.