No. Especially if the "cult" is known to be a high control, damaging cult.
To illustrate: How would you like to be around 4 or 5 years old with your parents dying or getting divorced, and some Jehovah's Witlesses adopted you. You know what Christmas is like. Around October, you look around at all the Halloween decorations, looking forward to trick or treat--and find out that you are not going to participate. There are no decorations in your place. You draw your adoptive parents a jack o'lantern, and get in trouble for it. The same happens when Christmas comes--you get in trouble for wanting Christmas items. You wonder why there is no Christmas tree--there isn't going to be any.
At a later stage, you find your play time is usurped. Until your adoption, you had plenty of time to play. Now, you are carted from door to door all day. That play time is gone. Seems that most of the fun trips are gone, too--replaced with field circus. Not to mention, having to sit still for 8 hours at a time at the a$$emblies, 3 times a year. You remember when summer vacations meant going to the amusement park, picnicking, camping, visiting friends from out of town, and hanging out around your neighborhood instead of being carted from door to door on a boring mission.
You start school. Your adoptive parents set you up for dorkhood, because there is so much you can't do. No holiday parties of any kind. No saluting the flag. No playing--associating with other children, except to witless to the, is forbidden. You are dissuaded from field trips, and cannot do anything that means staying after school. And, instead of playing, you are hauled out in field circus or have to study the washtowel or Kingdumb Misery. If you have a test or homework, that Kingdumb Misery or Washtowel--or field circus--take priority, leaving no time to properly do homework or study for your test. If you were in school before being adopted, you remember getting to do holidays, take part in field trips, and properly study for tests instead of being a witless.
This goes on. After a short time, you start being hounded to get baptized. You are only 9 or 10, and really need more time to make a decision properly. However, you are pushed to get baptized in case Armageddon comes tomorrow. At which point, school vacations are wasted pio-sneering. Other children will be looking forward to trips--some to Maine, some to the Adirondacks, some to the bayous of Alabama and Louisiana, some to California's redwood forests, some to Disney, some to England--and yes, a lucky few to New Zealand (where it is actually nice and cold during those months). You, on the other hand, have endless field circus to look forward to all damn summer--and that Grand Boasting Session where your music will be thrown away and stricter rules about field circus will be implemented. And, if you don't get your 50 hours a month during those months, you are going to be in for it at the end of the month.
Once you reach age 18 and college time, you find you are not going. No, not because apprenticeship and buying silver would give you better experience and help you earn more. But, because your adoptive parents think college is wicked. Apprenticeship is also frowned on, because you are going to regular pio-sneer. You will be working part time, making paltry wages and having to waste a good part of those wages on Jehovah crap. By now, your dreams are all gone because you didn't take the opportunities to develop talents and gifts. Your gift for math and science, dominant before adoption, are all gone. So, you cannot function outside the religion. You are stuck pio-sneering, and are afraid that you will get destroyed the minute you leave the cancer. Result: You grow old and die without reaching anywhere near your full potential.
And this assumes you are not adopted by one of the pedophiles, or child beaters, in the congregation. Virtually every single witless child faces this form of abuse, where they are deprived of opportunities. That is the main reason why I think witlesses, and other high-control cults and damaging cults, should not have their members being allowed to adopt.