Human beings adapt their language to the audience they interact with. To study the impact of audience and gender in a natural setting, we choose a domain where gender plays a particularly salient role: parenting. We collect posts from the three popular parenting Subreddits (i.e., topical communities on Reddit) r/Daddit, r/Mommit, and r/Parenting. These three Subreddits gather different audiences, respectively, self-identifying as fathers and mothers (ostensibly single-gender), and parents (explicitly mixed-gender). By selecting a sample of users who have published on both a single-gender and a mixed-gender Subreddit, we are able to explore both audience and gender effects. We analyse posts with word embeddings by adding the username as a token in the corpus. This way, we are able to compare user-tokens to word-tokens and measure their similarity. We also investigate individual differences in this context by comparing users who exhibit significant changes in their behaviour (high self-monitors) with those who show less variation (low self-monitors). Results show that r/Parenting users generally discuss a great diversity of topics while fathers focus more on advising others on educational and family matters. Mothers in r/Mommit distinguish themselves from other groups by primarily discussing topics such as medical care, sleep and potty training, and food. Both mothers and fathers celebrate parenting events and describe or comment on the physical appearance of their children with a single-gender audience. In terms of individual differences, we find that, especially on r/Parenting, high self-monitors tend to conform more to the norms of the Subreddit by discussing more of the topics associated with the Subreddit. In conclusion, this study shows how mothers and fathers express different concerns and change their behaviour for different group-based audiences.