Hi, 

You can add the field to your sign-up form and then it will show as a Custom Property under the subscribers profile.  Here’s an example where ask the customer who they are buying for on the pop-up we have on the site and it’s saved as a custom property:

Hey @BalandiTeam and @Manny Singh !

Manny is absolutely correct- you can store gender as a custom property. This is a great option if you’re collecting gender via signup forms or if you have that data to upload to customer profiles.

Another option is to use Klaviyo’s algorithm for predicted gender. Check out this blog post to learn more! https://www.klaviyo.com/blog/gender-predictive-attribute

You can find this in the segment dropdown by going to Predictive analytics about someone » Predicted Gender:

Best,

Kalie

To make this post complete, you can also send emails to clients asking them questions like gender. Not sure if people would react but it's an option. Link added below:

https://help.klaviyo.com/hc/en-us/articles/115005255248-How-to-Use-Buttons-to-Collect-Information-About-Your-Recipients

Furthermore, you can also run a flow to add or update profile properties like gender.