Microsoft has been developing something called Project Oxford which is a basically bundle of APIs and SDKs enabling developers to have the natural data analysis capabilities in their programs. Project Oxford contains APIs to detect or recognize faces, recognize voice, understanding voice commands and more. Microsoft has created a demonstration web site How-Old.net that demonstrates these features being developed by Microsoft. On this web site, they make use of the Face APIs to detect faces in a picture and estimate the age and the gender from these detected faces.
On the How-Old.net website, you can check and find out if it detects your age and gender correctly. Since the web site is designed by Microsoft, it is closely integrated with Bing. You can search for pictures of any of you favorite celebrities to find a picture containing the face of the person. You can choose to use on the these pictures or upload your own picture.
In order to use your own picture, click/touch on the button labeled Use your own video. If you are on your smart phone, then you will be given the options to capture your picture using the mobile phone camera. In both case, you can also select any picture file from your local storage disk.
As soon as the picture is selected, it starts to analyze the picture and in a few seconds labels all the faces with gender an age. This looks cool, but it is only a demo software. Besides it works only for a selected web sites. Microsoft mentions that the Face APIs are still n the beta mode and the age or gender calculations may not be correct.
Indeed after checking dozens of pictures on How-Old.net, I have realized that it fails almost all the time. For example a picture of Miley Cyrus was labeled at 33 years old female.
Conclusion: If you are a software developer then you can add some of the pictures on the How-Old.net website. It can process and tell you the age and gender of all the persons in the picture.
You can see a demo of the Face APIs at http://how-old.net/.