Here is my latest post:
Fertility Symbols, Feminine Principle and BA
In summary it talks about the BA baybayin symbols...
both of which are yonni symbols or fertility symbols.
I also talk about the fertility symbols of the lingling-o and the dinumug...
lingling-o on left and dinumug on right
(Source: Kipas Gallery - http://www.kipas.nl/Beads/BontFertSym.htm)
The lingling-o is a common ancient artifact symbolizing fertility found around Southeast Asia and the Philippines(ca. 500 B.C.–100 A.D.); dinumug is a fertility symbol and symbol of prosperity and love found in the Ifugao, Bontoc and other Cordillera regions of the northern Philippines.
This particular post at Baybayin Alive goes on to talk about how the fertility symbol shape could very well be the imagery from which the BA baybayin symbol (clefted version) evolved from.