From the numerous references to Phoebe Mayo on the internet, it seems clear to me that Nathaniel had one daughter named Phebe born 15.X.1691, married Mary on 28.X.1703, and named another daughter Phebe born June 1709. As Phebe married 23.IV.1724, it seems most likely to me that the correct Phebe was born in 1709.
This person was created through the import of Bwiki.ged on 03 April 2011. The following data was included in the gedcom. You may wish to edit it for readability.
Note: Sources: Family records and Ancestral File (TM), data as of 2 January
1996 which shows birthplace as Eastham, Barnstable, Massachusetts and shows her
with parents Nathaniel and Mary (Brown) which is incorrect as they were not
married until years after she was born, nor could it have been a second wife he
married after she was born. It shows another wife with no information. There
is no evidence I can find to suggest it is Nathaniel.
Date: 9 Dec 2001
Prior to import, this record was last changed 21:29:43 9 Dec 2001.
↑ "Eastham and Orleans, Mass., Vital Records", in Massachusetts Society of Mayflower Descendants. Mayflower Descendant: An Illustrated Quarterly Magazine of Pilgrim Genealogy, History and Biography, 8:90.
Phebee Mayo Daughter of Nathaniel & Mary Mayo born June 1709.
V.8, p.90/264885768 Eastham and Orleans; Massachusetts: Vital Records, 1621-1850 (Online Database: AmericanAncestors.org, New England Historic Genealogical Society, 2001-2016); MD (Mayflower Decendant) V.8, p.90 found in NEHGR V.123, p.204. This source is behind a paywall
It may be possible to confirm family relationships with Phebe by comparing test results with other carriers of her mitochondrial DNA.
However, there are no known mtDNA test-takers in her direct maternal line.
It is likely that these autosomal DNA test-takers will share DNA with Phebe: