1. Tell her that your adoptive parents don’t appreciate her existence. (This may startle her at first and then hurt. They certainly appreciated her existence when they raided her womb. She may wonder what changed but really, she will get over it. All “birth”moms get over it.)
2. Tell her that you are just answering her emails out of obligation and you are doing her a favor. It’s likely no one has done her and her family a favor since she was sent away to give birth to you alone (the nuns surrounding her don’t count). Since words are sometimes misconstrued, when you are clearly being rude, say that "and this is meant to be rude and hurtful to you".
3. Tell her that nature/nurture is nothing. Assure her, repeatedly, that nothing she has or does is in any way reflected in you. She was just your breeder. Her deed is done. Genetics is a crutch for the person who lacks an ability to be a unique individual.
4. Tell her she is needy and obsessive and it’s a bit too late for that. She should have needed you when she was 15 and doing you a favor by giving you a better life than she thought she could. Better yet, tell her she should have fought those drugs they gave her to sedate her when they took you from her. Come on. Surely, she was stronger than that? And tell her to save the tying in restraints sob story for someone else.
5. Tell her you really would prefer she not send you any gifts. The less you have of her around you the better. If she continues to send, invest in a big fat ol’ RETURN TO SENDER stamp. You can get one at your local office supply store.
6. Imply to her, subtly, repeatedly, through thinly disguised contempt, that you think she is a moronic boob. (After all, only village idiots give away their children) Repeatedly tell her to get a grip of herself and calm down even when she is not upset. She doubts herself as it is. You can really help her along by making your issues her issues. This is sure to send her over the edge she has been teetering on for years. Then you will really be rid of her.
7. Ask her how much she received in payment for the sale of you. When she says she got nothing, don’t believe her. Insist that your adoptive sibling cost 20K and you want to know how much you were worth. Did she buy a car with the money the agency gave her? Maybe take a vacation?
8. Tell her there is no such thing as primal wound, adoption trauma or the like. Tell her it’s all in her head and she a bit unstable and you were likely much better off without her after all.
9. Don’t answer her emails, or her phone calls, or letters for months or years. When she finally explodes with anxiety thinking you may be dead or something, explode back. Make your denial and avoidance of her into her issue. Refer to #6.
10. While doing all of the above, ask her to hang around while you grow up and decide if you want her in your life or not.
– source: a number of moms i know (including myself)