diff --git a/core/kotlinx-coroutines-io/src/main/kotlin/kotlinx/coroutines/experimental/io/ReaderJob.kt b/core/kotlinx-coroutines-io/src/main/kotlin/kotlinx/coroutines/experimental/io/ReaderJob.kt
index 14173ec..8b98788 100644
--- a/core/kotlinx-coroutines-io/src/main/kotlin/kotlinx/coroutines/experimental/io/ReaderJob.kt
+++ b/core/kotlinx-coroutines-io/src/main/kotlin/kotlinx/coroutines/experimental/io/ReaderJob.kt
@@ -22,8 +22,9 @@
 
 fun reader(coroutineContext: CoroutineContext,
            channel: ByteChannel,
+           parent: Job? = null,
            block: suspend ReaderScope.() -> Unit): ReaderJob {
-    val newContext = newCoroutineContext(coroutineContext)
+    val newContext = newCoroutineContext(coroutineContext, parent)
     val coroutine = ReaderCoroutine(newContext, channel)
     coroutine.initParentJob(newContext[Job])
     block.startCoroutine(coroutine, coroutine)
@@ -32,7 +33,8 @@
 
 fun reader(coroutineContext: CoroutineContext,
            autoFlush: Boolean = false,
-           block: suspend ReaderScope.() -> Unit): ReaderJob = reader(coroutineContext, ByteChannel(autoFlush), block)
+           parent: Job? = null,
+           block: suspend ReaderScope.() -> Unit): ReaderJob = reader(coroutineContext, ByteChannel(autoFlush), parent, block)
 
 private class ReaderCoroutine(context: CoroutineContext, channel: ByteChannel)
     : ByteChannelCoroutine(context, channel), ReaderJob, ReaderScope
diff --git a/core/kotlinx-coroutines-io/src/main/kotlin/kotlinx/coroutines/experimental/io/WriterJob.kt b/core/kotlinx-coroutines-io/src/main/kotlin/kotlinx/coroutines/experimental/io/WriterJob.kt
index 372f493..aceb24c 100644
--- a/core/kotlinx-coroutines-io/src/main/kotlin/kotlinx/coroutines/experimental/io/WriterJob.kt
+++ b/core/kotlinx-coroutines-io/src/main/kotlin/kotlinx/coroutines/experimental/io/WriterJob.kt
@@ -22,8 +22,9 @@
 
 fun writer(coroutineContext: CoroutineContext,
            channel: ByteChannel,
+           parent: Job? = null,
            block: suspend WriterScope.() -> Unit): WriterJob {
-    val newContext = newCoroutineContext(coroutineContext)
+    val newContext = newCoroutineContext(coroutineContext, parent)
     val coroutine = WriterCoroutine(newContext, channel)
     coroutine.initParentJob(newContext[Job])
     block.startCoroutine(coroutine, coroutine)
@@ -32,7 +33,8 @@
 
 fun writer(coroutineContext: CoroutineContext,
            autoFlush: Boolean = false,
-           block: suspend WriterScope.() -> Unit): WriterJob = writer(coroutineContext, ByteChannel(autoFlush), block)
+           parent: Job? = null,
+           block: suspend WriterScope.() -> Unit): WriterJob = writer(coroutineContext, ByteChannel(autoFlush), parent, block)
 
 private class WriterCoroutine(ctx: CoroutineContext, channel: ByteChannel)
     : ByteChannelCoroutine(ctx, channel), WriterScope, WriterJob