Buddy says:  When planning work related social events, it is important to consider the composition of your employees and how the planned events will affect them.  If employees do not drink for religious reasons, or reasons such as pregnancy, and they attend a work related social event where people are expected to drink, then there is a risk discrimination claims, either on religious grounds or on sex/pregnancy grounds.

In order to minimise the risks of such claims you should make sure that, where possible, events are not alcohol led, even if alcohol is to be provided.  You should also cater for those who do not drink alcohol, for example making sure that a variety of soft drinks are offered, and that there are suitable alternatives, for example non alcoholic wine or punch.  It is also a good idea to have a mix of social events that do not involve alcohol as well as ones that do.

Employer information:  You should always make sure that nobody feels offended or left out when it comes to company celebrations.  As well as feeling uncomfortable if they attend alcohol led events, the affected staff may also feel that their non-attendance will be punished, whether directly or indirectly.  Therefore, you should make it clear that attendance at such events is not compulsory.
It's also important that you keep an eye on how your other employees react to employees who do not wish to drink alcohol, and also how they react to measures the company takes to diversify its social events. Staff may feel disappointed if you break with tradition and plan events with less/no alcohol, which could lead to hostility.  If staff take this out on the non drinkers in the workforce then you could be facing claims of harassment.  In order to minimise such risks, employees should be reminded of any equal opportunities and/or anti harassment policies in place that state that such behaviour is unacceptable.  In line with this, disciplinary action should be taken against employees who harass or bully other employees who do not wish to drink.