The chosen method of self-disclosure is closely related to the goals of the person who is making the disclosure, which include the desired reaction on the part of the recipient(s) of the information. Three important types of self-disclosure theory focus on different aspects of that equation, as psychologist Stephen Lynn has discussed. This woman’s idea about disclosing her relationship will depend in part on her expectations from her parents, both in terms of their immediate reaction and anticipated longer-term consequences. Whether a letter is the appropriate vehicle depends on her goals but also on such factors as physical distance (perhaps they live far apart) and time elapsed since previous communication (perhaps they had been estranged, and a phone call or face to face contact seems invasive).

In equitable exchange theory, the emphasis is on reciprocity: the initiation of self-disclosure anticipates the exchange of information in a relationship of reciprocity. The information is also offered as an affirmation of trust. In the case described, the woman may feel it is important that her parents know that she wants to be honest with them and trusts them with her confidence. Another theory is that of attraction, in which the disclosure is based on liking and the desire for greater intimacy. While this may usually apply to potential friends or partners, the desire for intimacy with her parents could be motivating this woman. A third theoretical approach stresses the importance of the information, which seems high in this case. The woman may be responding to an actual request or verbal or behavioral cues indicating her parents have relevant questions, and she is ready to answer them.

There are two issues here, one being whether a letter is an appropriate genre and the other being Sara's actual situation.

Given the closeness of the familial relationship, this level of self-disclosure is appropriate. In general, it is not appropriate to share personal information with co-workers or strangers, but it is appropriate to share it with family or close friends. That being said, how people should best handle coming out to their parents really depends on cultural and personal context. In countries such as Saudi Arabia or Uganda, where homosexuality is illegal, the person might not want to inform his or her parents for fear of making them legally complicit. 

In general, a letter is considered less intimate than an in-person discussion or telephone call but less superficial or casual than an email or text. While its limited level of interactivity can make it seem cold for an important child-parent communication, it does allow a level of careful thought and editing that can be useful in a fraught situation. If the person is on good terms with his or her parents, a visit might be more appropriate, but if the news could potentially be received badly, a letter followed by a visit or a phone call might be a good strategy.

Next, one needs to think of context. If the person lives in Canada or Sweden, and his or her two mothers are married, they would probably be delighted to learn of the relationship. If the parents are homophobic, sharing details of the relationship might not elicit a positive response. In the case of very elderly homophobic parents, discretion might be the better part of valor.