In some countries laws require that given names clearly identify gender. In other societies a surname or patronymic will hold indications of a gender. However, in most cultures names may be given which are not uniquely male or female. Furthermore, a name which is one gender in one culture may be the other gender in another culture. As the global population is mobile, one can no longer state that a name found in one place is that gender - it may be an immigrant with the other gender.
The gender to which names are given may change over time (more usually from male to female):
Names which have different genders in different cultures: Jean (male, French; female Anglo Saxon); Jan (female Anglo Saxon; Male Czech); José (male) United States; female The Netherlands); Joan (male Catalan; female United Kingdom).
Gender can usually not be identified without corroborating information or a dialogue with a customer. Do not put trust in gender coding programs. Assign gender at the data collection stage, or not at all - making an error in the gender of your customer in communication with them will have a major negative effect.
If attempts to assign a gender is made after data collection, one must be sure that one knows which name is the given name and which the surname/other names. As given names may be used as surnames, and vie versa, for example James Joyce, the gender coding must be carried out on the correct string.
Gender cannot always be assigned from a form of address. Forms of address are assigned in many cultures from aspects other than gender, such as age and academic achievement. Gender-neutral forms of address include Dr, Professor. Those that appear to indicate a gender, such as Mr may mislead - this may indicate a female (as well as male) surgeon in the United Kingdom or a female (as well as male) barrister in The Netherlands
If a gender is unknown, gender-neutral communication is usually a better option than assigning and using an incorrect gender.