There were two John Skillicorns bapt in 1725/26 in Lonan. One bapt 9 Feb 1725/26, son of John S. with no place or mother given, and the other [as Lois said] bapt 25 Dec.1725 son of Thomas Skillicorn, whose details I haven't looked up on the parish register.
There were at least six John Skillicorn fathers having children baptised in Lonan in the 1720s & 1730s. Of "Ballaragh", of "Bane", of "the Fells", of the "Mountains", in "Skinscoe", and "in Laxey", plus others with no place name given. It is only by looking at the parish registers combined with wills that you can build up a picture of who was where and to whom they were married. For example, burials have "Old Elizabth Skillicorn als Ceiggeen of Ballaragh Dec. 21 1721", "Isable Skillicorn als Colleash of Laxey Apr 24 1722", "Mary Skillicorn who died at Capt. Oates's, Oct 15 1723", "Margret Skillicorn dau to Tho: and her half sister Mary Karran dau to Gilbt. May 28 1724". The latter entry was in a list "All these died in the small pox".
There is no way you would be able to see these relationships in indexes.
Sue