Indeed Isabel is one of those names used for both sexes in Mexico and other countries.
The nickname for the girls is Chabela, and for the boys is Chabelo.
Here are a couple of examples:

http://www.salondelafama.com.mx/salondelafama/trono/alfasf.asp?x=164
http://www.mipueblo.mx/27/2250/jose-isabel-nava-castillo-chabelo/

Regards,
Victoriano Navarro

Thank you Victoriano…I have added another great grand uncle to my tree.

I have come across Ysabel as a male name once when indexing.
Raquel Ruiz

Sent from my Verizon Wireless Phone

—– Reply message —–
From: rvr_jr@msn.com
To:
Subject: [Nuestros Ranchos] Gender Question
Date: Tue, Apr 30, 2013 12:01 pm

My paternal great grandmother was Maria Ysabel Caballero, baptised 16Dec1860 in Totatiche, Jalisco. Daughter of Tranquilino Caballero y Maria Juliana de la Trinidad Avila

source:
https://familysearch.org/pal:/MM9.3.1/TH-1-18685-15759-46?cc=1874591&wc=M99L-2C8:n1322479794

I have now found another child of Tranquilino Caballero y Trinidad D’abila, baptised on 01Mar1864 in Tlaltenango de Sanchez Ramon, Zacatecas.

source:
https://familysearch.org/pal:/MM9.3.1/TH-1-15530-33887-83?cc=1804458&wc=M99V-NGZ:n592675783

This record indicates Ysabel was a male child. Was this name actually used for both sexes? Any insight would be greatly appreciated.

Saludos,
Roy

Ysabel and Ynes/Ygnes are used frequently for males in Jerez, Zac
Linda

________________________________
From: “ruiz.raquel061@gmail.com”
To: research@nuestrosranchos.org
Sent: Wednesday, May 1, 2013 11:11 AM
Subject: Re: [Nuestros Ranchos] Gender Question

I have come across Ysabel as a male name once when indexing.
Raquel Ruiz

Sent from my Verizon Wireless Phone

—– Reply message —–
From: rvr_jr@msn.com
To:
Subject: [Nuestros Ranchos] Gender Question
Date: Tue, Apr 30, 2013 12:01 pm

My paternal great grandmother was Maria Ysabel Caballero, baptised 16Dec1860 in Totatiche, Jalisco.  Daughter of Tranquilino Caballero y Maria Juliana de la Trinidad Avila

source:
https://familysearch.org/pal:/MM9.3.1/TH-1-18685-15759-46?cc=1874591&wc=M99L-2C8:n1322479794

I have now found another child of Tranquilino Caballero y Trinidad D’abila, baptised on 01Mar1864 in Tlaltenango de Sanchez Ramon, Zacatecas.

source:
https://familysearch.org/pal:/MM9.3.1/TH-1-15530-33887-83?cc=1804458&wc=M99V-NGZ:n592675783

This record indicates Ysabel was a male child.  Was this name actually used for both sexes?  Any insight would be greatly appreciated.

Saludos,
Roy