It is keyed for all notice types, but only when there is an indication of gender in the ad, such as husband, wife, sister, his, her, Mr, Mrs, etc.

The same rules apply to spouse gender - if there is an indication of the spouse's gender in the ad it should be keyed. It isn't always redundant because sometimes the spouse's gender is the only one that is specified in the ad, for instance there are some engagements along the lines of "Mr and Mrs Smith announce the engagement of their daughter Jane to John Brown". In this case, we are supposed to key the bride as spouse, so that is obviously Jane and we can key spouse gender as "female" because she is described as "daughter", but John Brown's gender is not referred to in the notice so would not be keyed.